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Objective: To explore the genetic etiology of a Chinese pedigree affected with Branchio-oculo-facial syndrome (BOFS) and summarize the prenatal phenotype of BOFS patients., Methods: A pedigree with BOFS which had presented at the Genetics and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University in December 2021 was selected as the study subject. Clinical data of the pedigree was collected. The fetus was subjected to routine prenatal ultrasound scan. Trio-whole exome sequencing (trio-WES) was carried out for the fetus and its parents, and candidate variant was verified by Sanger sequencing. Relevant literature was searched from the database to summarize the prenatal phenotype of BOFS patients., Results: Ultrasound exam suggested the fetus had cleft lip and palate. Its father had presented with high palatal arch, prematurely grayed hair, occult cleft lip, congenital preauricular fistula, red-green color blindness and unilateral renal agenesis. Its grandfather also had high palatal arch, prematurely gray hair, protruding ears, congenital preauricular fistula and hearing disorders. Trio-WES revealed that the fetus and its father had both harbored a heterozygous c.890-1G>A variant of the TFAP2A gene. The same variant was not found in its mother. Sanger sequencing confirmed that its grandfather had also harbored the same variant. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as likely pathogenic (PVS1+PM2_Supporting). Combined with 36 similar cases retrieved from the literature, the prenatal phenotypes of BOFS patients had included growth restriction (25/37), renal abnormalities (10/37), cleft lip and palate (5/37) and oligohydramnios (5/37)., Conclusion: The c.890-1G>A variant of the TFAP2A gene probably underlay the pathogenesis of BOFS in this pedigree. Discovery of the novel variant has enriched the mutational spectrum of the TFAP2A gene. The common prenatal phenotypes of BOFS have included growth restriction, renal abnormalities, cleft lip and palate and oligohydramnios. Delineation of the intrauterine phenotype of BOFS may facilitate its prenatal diagnosis, clinical diagnosis, treatment and genetic counseling.

Branchio-oto-renal (BOR) and branchio-otic (BO) syndromes are characterized by anomalies affecting the ears, often accompanied by hearing loss, as well as abnormalities in the branchial arches and renal system. These syndromes exhibit a broad spectrum of phenotypes and a complex genomic landscape, with significant contributions from the EYA1 gene and the SIX gene family, including SIX1 and SIX5 . Due to their diverse phenotypic presentations, which can overlap with other genetic syndromes, molecular genetic confirmation is essential. As sequencing technologies advance, whole-genome sequencing (WGS) is increasingly used in rare disease diagnostics. We explored the genomic landscape of 23 unrelated Korean families with typical or atypical BOR/BO syndrome using a stepwise approach: targeted panel sequencing and exome sequencing (Step 1), multiplex ligation-dependent probe amplification (MLPA) with copy number variation screening (Step 2), and WGS (Step 3). Integrating WGS into our diagnostic pipeline detected structure variations, including cryptic inversion and complex genomic rearrangement, eventually enhancing the diagnostic yield to 91%. Our findings expand the genomic architecture of BOR/BO syndrome and highlight the need for WGS to address the genetic diagnosis of clinically heterogeneous rare diseases.

Objective: To investigate the clinical phenotype of a family with branchio-oto syndrome （BOS） and to explore the genetic etiology of the syndrome in this family. Methods: Clinical data were collected from a child diagnosed with BOS and his family members. Genomic DNA was extracted from peripheral blood of the proband and his family members. Whole-exome sequencing was performed, and the mutation sites were verified and analyzed by Sanger sequencing. Results: The family consists of two generations with four members, three of whom exhibit the phenotype. Two members have hearing loss and bilateral preauricular fistulas and bilateral branchial cleft fistulas. One member has bilateral preauricular fistulas and bilateral branchial cleft fistulas. All of which were in line with the clinical diagnosis of gill ear syndrome, the inheritance mode of the family was autosomal dominant inheritance, genetic testing showed that all members of the family had c. 1744delC（p. L592Cfs*47） mutation in the EYA1 gene, while unaffected members have the wild-type allele at this locus. This mutation is a frameshift mutation, which results in the early appearance of the stop codon, and has not been reported so far. According to ACMG guidelines, the variant was preliminarily determined to be suspected pathogenic. Conclusion: The newly discovered EYA1c. 1744delC（p. L592Cfs*47） mutation in this family is the pathogenic mutant gene of the patients in this family, which further expands the mutation spectrum of EYA1 gene, gives us a new understanding of the disease, and provides an important reference for clinical diagnosis and genetic counseling., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

Hearing in infants is essential for brain development, acquisition of verbal language skills, and development of social interactions. Therefore, it is important to diagnose hearing loss soon after birth so that interventions can be provided as early as possible. Most newborns in the United States are screened for hearing deficits and commercially available next-generation sequencing hearing loss panels often can identify the causative gene, which may also identify congenital defects in other organs. One of the most prevalent autosomal dominant congenital hearing loss syndromes is branchio-oto-renal syndrome (BOR), which also presents with defects in craniofacial structures and the kidney. Currently, mutations in three genes, SIX1, SIX5, and EYA1, are known to be causative in about half of the BOR patients that have been tested. To uncover new candidate genes that could be added to congenital hearing loss genetic screens, we have combined the power of Drosophila mutants and protein biochemical assays with the embryological advantages of Xenopus, a key aquatic animal model with a high level of genomic similarity to human, to identify potential Six1 transcriptional targets and interacting proteins that play a role during otic development. We review our transcriptomic, yeast 2-hybrid, and proteomic approaches that have revealed a large number of new candidates. We also discuss how we have begun to identify how Six1 and co-factors interact to direct developmental events necessary for normal otic development., (© 2023 The Authors. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution published by Wiley Periodicals LLC.)

Objective: Branchio-oto-renal syndrome (BOR, OMIM#113,650) is a rare autosomal dominant disorder that presents with a variety of symptoms, including hearing loss (sensorineural, conductive, or mixed), structural abnormalities affecting the outer, middle, and inner ear, branchial fistulas or cysts, as well as renal abnormalities.This study aims to identify the pathogenic variants by performing genetic testing on a family with Branchio-oto-renal /Branchio-otic (BO, OMIM#602,588) syndrome using whole-exome sequencing, and to explore possible pathogenic mechanisms., Methods: The family spans 4 generations and consists of 9 individuals, including 4 affected by the BOR/BO syndrome. Phenotypic information, including ear malformation and branchial cleft, was collected from family members. Audiological, temporal bone imaging, and renal ultrasound examinations were also performed. Whole-exome sequencing was conducted to identify candidate pathogenic variants and explore the underlying molecular etiology of BOR/BO syndrome by minigene experiments., Results: Intra-familial variability was observed in the clinical phenotypes of BOR/BO syndrome in this family. The severity and nature of hearing loss varied in family members, with mixed or sensorineural hearing loss. The proband, in particular, had profound sensorineural hearing loss on the left and moderate conductive hearing loss on the right. Additionally, the proband exhibited developmental delay, and her mother experienced renal failure during pregnancy and terminated the pregnancy prematurely. Genetic testing revealed a novel heterozygous variant NM_000503.6: c.639 + 3 A > C in the EYA1 gene in affected family members. In vitro minigene experiments demonstrated its effect on splicing. According to the American College of Medical Genetics (ACMG) guidelines, this variant was classified as likely pathogenic., Conclusion: This study highlights the phenotypic heterogeneity within the same family, reports the occurrence of renal failure and adverse pregnancy outcomes in a female patient at reproductive age with BOR syndrome, and enriches the mutational spectrum of pathogenic variants in the EYA1 gene., (© 2024. The Author(s).)

Objective: To assess the clinical features and CT diagnostic characteristics of Branchio-Oto-Renal or Branchio-Oto Syndrome . Methods: The temporal CT findings and clinical features observations of 13 patients with Branchio-Oto-Renal Syndrome (BORS) or Branchio-Oto Syndrome(BOS) confirmed by genetic testing were retrospectively analyzed. There were 8 males and 5 females, aged from 1 to 39 years, with a median age of 9 years, in which 3 pairs (6 cases) were parent-child relationship. Results: All of 13 cases had hearing loss and preauricular fistula, 11 cases accompanied by 2nd branchial fistulas. There were 20 ears of mixed hearing loss, 3 ears of sensorineural hearing loss, and 2 ears of conductive hearing loss. The mutation point of gene testing was located in EYA1 in 12 cases and SIX1 in 1 case. Twenty ears showed gradually narrowing of the diameter of basal turn, with hypoplasia in the second turn and aplasia in apical turn. There were irregular wall of vestibule and horizontal semicircular canal in 10 ears,widened vestibular in 7 ears, and vestibular fusion with horizontal semicircular canal in 3 ears. Three ears had an enlarged vestibular aqueduct, 8 ears showed enlargement of internal auditory canal. Seventeen ears had adhesion of malleolus to tympanic cavity. Six ears could not measured the incudostapedial joint angle by reason of tympanic inflammatory cover, 3 ears could not show incudostapedial joint, and 8 ears showed the incudostapedial joint angle more than 122°. Six ears showed poor oval window, and 1 ear had poor round window. Eighteen ears showed distended eustachian tube, and accompanied by tympanic or mastoiditis in 11 ears. Anterolateral shift of tympanum was found in 22 ears, 17 ears had low middle cranial fossa, and 3 ears had stenotic external auditory canal. Conclusions: Cochlear dysplasia, ossicular chain malformation and distended eustachian tube comprise the characteristic CT signs of BOS/BORS, which possesses versatile and complex CT findings. Temporal CT can accurately assess the important structures such as cochlea, ossicles, vestibule, semicircular canal, vestibular aqueduct and internal auditory canal. Combing with the clinical characteristics of bilateral, mixed hearing loss, preauricular fistula and branchial fistula can provide valuable information for early diagnosis and treatment.

The association between ear and kidney anomalies has long been recognized. However, little is known about the underlying mechanisms. In the last two decades, embryonic development of the inner ear and kidney has been studied extensively. Here, we describe the developmental pathways shared between both organs with particular emphasis on the genes that regulate signalling cross talk and the specification of progenitor cells and specialised cell types. We relate this to the clinical features of oto-renal syndromes and explore links to developmental mechanisms., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

Introduction: Branchio-oto-renal syndrome (BOR syndrome) is a rare genetic disorder with an incidence of 1 in 40,000, affecting the development of multiple organs, including the branchio, ear, and kidney. It is responsible for 2% of childhood deafness. Currently, variants in the coding regions of the main causative genes, such as EYA1, SIX1, and SIX5, explain only half of the disease's etiology. Therefore, there is a need to explore the non-coding regions, which constitute the majority of the genome, especially the regulatory regions, as potential new causative factors., Method: In this study, we focused on the EYA1 gene, which accounts for over 40% of BOR syndrome cases, and conducted a screening of candidate enhancers within a 250-kb region upstream and downstream of the gene using comparative genomics. We characterized the enhancer activities of these candidates in zebrafish using the Tol2 transposon system., Results: Our findings revealed that out of the 11 conserved non-coding elements (CNEs) examined, four exhibited enhancer activity. Notably, CNE16.39 and CNE16.45 displayed tissue-specific enhancer activity in the ear. CNE16.39 required the full-length 206 bp sequence for inner-ear-specific expression, while the core functional region of CNE16.45 was identified as 136 bp. Confocal microscopy results demonstrated that both CNE16.39 and CNE16.45 drove the expression of GFP in the sensory region of the crista of the inner ear in zebrafish, consistent with the expression pattern of eya1., Conclusion: This study contributes to the understanding of the regulatory network governing EYA1 expression and offers new insights to further clarify the pathogenic role of EYA1 in BOR syndrome., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Otofaciocervical syndrome (OTFCS) is a rare genetic disorder of both autosomal recessive and autosomal dominant patterns of inheritance. It is caused by biallelic or monoallelic mutations in PAX1 or EYA1 genes, respectively. Here, we report an OTFCS2 female patient of 1st consanguineous healthy parents. She manifested facial dysmorphism, hearing loss, intellectual disability (ID), and delayed language development (DLD) as the main clinical phenotype. The novel homozygous variant c.1212dup (p.Gly405Argfs*51) in the PAX1 gene was identified by whole exome sequencing (WES), and family segregation confirmed the heterozygous status of the mutation in the parents using the Sanger sequencing. The study recorded a novel PAX1 variant representing the sixth report of OTFCS2 worldwide and the first Egyptian study expanding the geographic area where the disorder was confined., (© 2023. The Author(s).)

Background: Branchio-oto-renal (BOR) syndrome is an inherited multi-systemic disorder. Auricular and branchial signs are highly suggestive of BOR syndrome but often develop insidiously, leading to a remarkable misdiagnosis rate. Unlike severe morphological abnormalities of kidneys, knowledge of glomerular involvement in BOR syndrome were limited., Case Presentation: Three cases, aged 8 ~ 9 years, visited pediatric nephrology department mainly for proteinuria and renal insufficiency, with 24-h proteinuria of 23.8 ~ 68.9 mg/kg and estimated glomerular filtration rate of 8.9 ~ 36.0 mL/min/1.73m 2 . Moderate-to-severe albuminuria was detected in case 1, while mixed proteinuria was detected in case 2 and 3. Insidious auricular and branchial fistulas were noticed, all developing since early childhood but being neglected previously. EYA1 variants were confirmed by genetic testing in all cases. Delay in diagnosis was 8 ~ 9 years since extra-renal appearances, and 0 ~ 6 years since renal abnormalities. In case 1, therapy of glucocorticoid and immunosuppressive agents to accompanying immune-complex mediated glomerulonephritis was unsatisfying., Conclusions: BOR syndrome is a rare cause of proteinuria and abnormal kidney function and easily missed, thus requiring more awareness. Careful medical history taking and physical examination are essential to early diagnosis. Massive proteinuria was occasionally seen in BOR syndrome, which might be related to immune complex deposits. A novel pathogenic variant (NM_000503.6 (EYA1): c.1171delT p.Ser391fs*9) was firstly reported., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Branchio-oto-renal (BOR)/branchio-otic (BO) syndrome is a rare disorder and exhibits clinically heterogenous phenotypes, marked by abnormalities in the ear, branchial arch, and renal system. Sporadic cases of atypical BOR/BO syndrome have been recently reported; however, evidence on genotype-phenotype correlations and molecular mechanisms of those cases is lacking. We herein identified five SIX1 heterozygous variants (c.307dupC:p.Leu103Profs*51, c.373G>A:p.Glu125Lys, c.386_391del:p.Tyr129_Cys130del, c.397_399del:p.Glu133del, and c.501G>C:p.Gln167His), including three novel variants, through whole-exome sequencing in five unrelated Korean families. All eight affected individuals with SIX1 variants displayed non-syndromic hearing loss (DFNA23) or atypical BO syndrome. The prevalence of major and minor criteria for BOR/BO syndrome was significantly reduced among individuals with SIX1 variants, compared to 15 BOR/BO syndrome families with EYA1 variants. All SIX1 variants interacted with the EYA1 wild-type; their complexes were localized in the nucleus except for the p.Leu103Profs*51 variant. All mutants also showed obvious but varying degrees of reduction in DNA binding affinity, leading to a significant decrease in transcriptional activity. This study presents the first report of SIX1 variants in South Korea, expanding the genotypic and phenotypic spectrum of SIX1 variants, characterized by DFNA23 or atypical BO syndrome, and refines the diverse molecular aspects of SIX1 variants according to the EYA1-SIX1-DNA complex theory., (© 2023. The Author(s).)

Objectives: To explore the phenotypes and genotypes of patients with branchio-oto-renal (BOR) and branchio-otic (BO) syndrome, and to analyze the middle ear surgery outcomes qualitatively and quantitatively, proposing a factor usefully prognostic of surgical outcomes., Study Design: Retrospective cohort study., Setting: Tertiary referral center., Patients: Eighteen patients with BOR/BO syndrome in 12 unrelated Korean families., Intervention: Middle ear surgery, including either stapes surgery or ossicular reconstruction., Main Outcome Measure: Clinical phenotypes, genotypes, and middle ear surgery outcomes., Results: Eight probands (66.7%) were confirmed genetically; the condition segregated as a dominant or de novo trait. Six EYA1 heterozygous variants were identified by exome sequencing and multiplex ligation-dependent probe amplification. All variants were pathogenic or likely pathogenic based on the ACMG/AMP guidelines. Two novel EYA1 frameshift variants (p.His373Phefs*4 and p.Gln543Asnfs*90) truncating a highly conserved C-terminal Eya domain were identified, expanding the genotypic spectrum of EYA1 in BOR/BO syndrome. Remarkably, middle ear surgery was individualized to ensure optimal audiological outcomes and afforded significant audiological improvements, especially in BOR/BO patients without enlarged vestibular aqueducts (EVAs). A significant difference in air-bone gap closure after middle ear surgery was noted between the two groups even after adjusting for confounders: -20.5 dB in ears without EVAs (improvement) but 0.8 dB in ears with EVAs (no change or deterioration). Furthermore, the success rate was significantly associated with the absence of EVA., Conclusions: The results of this study were against the notion that middle ear surgery is always contraindicated in patients with BOR/BO syndrome, and an EVA could be a negative prognostic indicator of middle ear surgery in BOR/BO patients. This may aid to determine the strategy of audiological rehabilitation in patients with BOR/BO syndrome., (Copyright © 2023, Otology & Neurotology, Inc.)

Developmental senescence is a form of programmed senescence that contributes to morphogenesis during embryonic development. We showed recently that the SIX1 homeoprotein, an essential regulator of organogenesis, is also a repressor of adult cellular senescence. Alterations in the SIX/EYA pathway are linked to the human branchio-oto-renal (BOR) syndrome, a rare congenital disorder associated with defects in the ears, kidneys and branchial arches. Here, we have used Six1-deficient mice, an animal model of the BOR syndrome, to investigate whether dysfunction of senescence underpins the developmental defects associated with SIX1 deficiency. We have focused on the developing inner ear, an organ with physiological developmental senescence that is severely affected in Six1-deficient mice and BOR patients. We show aberrant levels and distribution of senescence markers in Six1-deficient inner ears concomitant with defective morphogenesis of senescent structures. Transcriptomic analysis and ex vivo assays support a link between aberrant senescence and altered morphogenesis in this model, associated with deregulation of the TGFβ/BMP pathway. Our results show that misregulation of embryo senescence may lead to genetic developmental disorders, significantly expanding the connection between senescence and disease., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

Unexplained diarrhea and cholestasis are common clinical phenotypes in newborns, indicating there is only a little common genetic basis for these conditions. However, it has been reported that defects in the UNC45A gene can lead to osteo-oto-hepato-enteric syndrome. However, to date, only 10 patients with this syndrome have been reported in 2 studies; therefore, there is still a lack of analysis regarding the correlation between disease phenotype and genotype. Trio-whole exome sequencing was conducted using DNA samples from a newborn with congenital diarrhea and cholestasis from a Chinese Han family. The UNC45A variants were verified using Sanger sequencing. In addition, we applied a crystal structure model to analyze the potential hazards associated with the variants. The plasmids were constructed in vitro and transfected into human 293T cells for Western blot (WB) analysis. After the mutant protein was fused with the Green Fluorescent Protein label, intracellular localization was observed using laser confocal microscopy. The gene detection results showed that the UNC45A gene of the newborn examined in the present study harbored the compound heterozygous variants p.Arg819Ter, and p.Leu237Pro; this was confirmed via Sanger sequencing. Analysis of the Leu237Pro crystal structure model suggested that this variant may decrease local structural stability and affect protein function. The Western blot and laser confocal microscopy observation results suggested that the Leu237Pro mutation leads to reduced protein expression, while the Arg819Ter mutation completely inhibits the expression of the protein. The compound heterozygous variants of UNC45A (p.Arg819Ter and p.Leu237Pro) may be pathogenic factors of congenital diarrhea and cholestasis in this neonatal patient. Therefore, UNC45A deficiency should be considered when intractable diarrhea and cholestasis occur in newborns., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Objective: To screen the causative genes of five families with branchio-oto-renal syndrome (BORS) or branchio-oto syndrome(BOS) and to analyze the phenotypic characteristics and clinical management strategies of patients. Methods: Five families with BORS/BOR from December 2018 to September 2021 were recruited, information of patients, including family history and medical history, was collected, and genealogies were drawn. The examinations concerning audiology, nephrology, and radiology were performed on the affected individuals. Peripheral blood was obtained for DNA extraction, then next-generation sequencing technology was used to screen candidate variants associated with BORS/BOS. Based on patient's clinical results, the appropriate interventions were recommended and implemented. Results: Eight individuals were diagnosed with BOS or BORS. Of the eight patients, all had hearing loss, preauricular pits and ear malformations, and only four presented with branchial cleft fistulae or cysts. Except for two patients(5-I-2, 5-II-2) who did not undergo renal examination, the remaining six lacked renal abnormalities. Genetic analysis identified four likely pathogenic or pathogenic EYA1 variants (c.1715G>T, c.1140+1G>A, c.639G>C, c.1475+1G>C; NM_000503.6), and c.1715G>T was first reported in this study. Middle ear ossicular reconstruction was performed in 1-II-2,2-I-2 and 3-II-2, but did not yield the expected results; then hearing aids and cochlear implantation were recommended and achieved satisfactory results. Conclusions: Next-generation sequencing technology facilitates the diagnosis and genetic counseling of BORS/BOS. Hearing loss, preauricular pits, ear malformations and branchial cleft fistulae or cysts are the most common manifestations of patients in this study. Middle ear surgeries for improving hearing loss may have some limitations in BORS/BOS patients, and hearing aids and cochlear implantation can contribute to hearing gains.

Background: Branchio-Oto-Renal (BOR) Syndrome is a rare autosomal disorder with a wide variety of clinical manifestations and a high degree of heterogeneity. Typical clinical manifestations of BOR syndrome include deafness, preauricular fistula, abnormal gill slits, and renal malformations. However, atypical phenotypes such as congenital hip dysplasia, congenital heart anomaly or facial nerve paresis are rare in BOR syndrome, and this might be easily misdiagnosed with other congenital disorders., Case Presentation: We report a 5-month-old boy of BOR syndrome with "congenital heart defects and proteinuria" as clinical features. Initially, as this case mainly presented with symptoms of recurrent respiratory infections and was found to be with congenital heart disease and proteinuria at the local hospital, but he only was diagnosed with congenital heart disease combined with pulmonary infection and anti-infective and supportive treatment was given. Subsequently, during the physical examination at our hospital, left side preauricular pit and branchial fistulae on the right neck were found. Subsequent evaluation of auditory brainstem response and distortion product otoacoustic emission were revealed sensorineural hearing impairment. Results of renal ultrasonography showed small kidneys. Genetic analysis revealed a microdeletion at chromosome 8q13.2-q13.3 encompassing EYA1 gene, this patient was finally diagnosed with BOR syndrome. Then, this patient received transcatheter patent ductus arteriosus closure and hearing aid treatment. Proteinuria, renal function and hearing ability are monitoring by nephrologist and otologist. The patient is currently being followed up until 3 months after discharge and his condition is stable., Conclusion: Careful physical examination, detailed history and the implementation of diagnostic laboratory tests can reduce the incidence of misdiagnosis. Genetic sequencing analysis of patients is a key guide to the differential diagnosis of BOR syndrome., (© 2022. The Author(s).)

Background and Purpose: An "unwound" or "offset" cochlea has been described as a characteristic imaging feature in patients with branchio-oto-renal syndrome, and recently recognized to be associated in particular to those with EYA1 gene mutations. Determination of this feature has traditionally relied on subjective visual assessment. Our aim was to establish an objective assessment method for cochlear offset (the cochlear turn alignment ratio) and determine an optimal cutoff turn alignment ratio value that separates individuals with EYA1 -branchio-oto-renal syndrome from those with SIX1 -branchio-oto-renal syndrome and healthy controls., Materials and Methods: Temporal bone CT or MR imaging from 40 individuals with branchio-oto-renal syndrome and 40 controls was retrospectively reviewed. Cochlear offset was determined visually by 2 independent blinded readers and then quantitatively via a standardized technique yielding the cochlear turn alignment ratio. The turn alignment ratio values were compared between cochleae qualitatively assessed as "not offset" and "offset." Receiver operating characteristic analysis was used to determine the ability of the turn alignment ratio to differentiate between these populations and an optimal cutoff turn alignment ratio value. Cochlear offset and turn alignment ratio values were analyzed for each branchio-oto-renal syndrome genotype subpopulation and for controls., Results: The turn alignment ratio can accurately differentiate between cochleae with and without an offset ( P  < .001). The optimal cutoff value separating these populations was 0.476 (sensitivity = 1, specificity = 0.986, J = 0.986). All except 1 cochlea among the EYA1 -branchio-oto-renal syndrome subset and all with unknown genotype branchio-oto-renal syndrome had a cochlear offset and a turn alignment ratio of <0.476. All except 1 cochlea among the SIX1 -branchio-oto-renal syndrome subset and all controls had no offset and a turn alignment ratio of >0.476., Conclusions: There is a statistically significant difference in turn alignment ratios between offset and nonoffset cochleae, with an optimal cutoff of 0.476. This cutoff value allows excellent separation of EYA1 -branchio-oto-renal syndrome from SIX1 -branchio-oto-renal syndrome and from individuals without branchio-oto-renal syndrome or sensorineural hearing loss. The turn alignment ratio is a reliable and objective metric that can aid in the imaging evaluation of branchio-oto-renal syndrome., (© 2022 by American Journal of Neuroradiology.)

Background: Branchio-oto-renal (BOR) syndrome is an autosomal-dominant disorder characterized by branchial arch anomalies, hearing loss, and kidney defects. Mutations in the human EYA1 gene have been reported associated with BOR syndrome. Here we identified that a novel variant, EYA1: NM&#95;000503.4: c.827-1G > C (Intron 8, shear mutation) was associated with BOR in a fetus of a Chinese family., Case Presentation: Prenatal ultrasound examination showed that both kidneys of the fetus were small and the echo of both kidneys was enhanced. The amount of amniotic fluid was normal, and no other structural abnormalities of the fetus were found. Fetal umbilical cord blood puncture was performed. No abnormality was found in karyotyping and chromosomal microarray analysis (CMA) results. Thus, we performed a trio-based whole exome sequencing (WES), and found that the fetus carried a novel homozygous variant, EYA1: NM&#95;000503.4: c.827-1G > C (Intron 8, shear mutation), but the parents do not have this mutation. The variation sites of fetus and parents were verified by Sanger sequencing to clarify the source of pathogenic variation., Conclusion: Combined with fetal imaging examination, the novel variation of EYA1: NM&#95;000503.4: c.827-1G > C is the cause of fetal renal dysplasia. This case report indicates that the early use of appropriate technology can clarify the etiology of fetal disease and guide prognosis consultation., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Branchio-oto-renal syndrome (BOR) is an autosomal dominant disorder characterized by deafness, branchiogenic malformations and renal abnormalities. Pathogenic variants in EYA1, SIX1 and SIX5 genes cause almost half of cases; copy number variants (CNV) and complex genomic rearrangements have been revealed in about 20% of patients, but they are not routinely and commonly included in the diagnostic work-up., Case Presentation: We report two unrelated patients with BOR syndrome clinical features, negative sequencing for BOR genes and the identification of a 2.65 Mb 8q13.2-13.3 microdeletion., Conclusions: We highlight the value of CNV analyses in high level of suspicion for BOR syndrome but negative sequencing for BOR genes and we propose an innovative diagnostic flow-chart to increase current detection rate. Our report confirms a mechanism of non-allelic homologous recombination as causing this recurrent 8q13.2-13.3 microdeletion. Moreover, considering the role of PRDM14 and NCOA2 genes, both involved in regulation of fertility and deleted in our patients, we suggest the necessity of a longer follow-up to monitor fertility issues or additional clinical findings., (© 2022. The Author(s).)

Mcrs1 is a multifunctional protein that is critical for many cellular processes in a wide range of cell types. Previously, we showed that Mcrs1 binds to the Six1 transcription factor and reduces the ability of the Six1-Eya1 complex to upregulate transcription, and that Mcrs1 loss-of-function leads to the expansion of several neural plate genes, reduction of neural border and pre-placodal ectoderm (PPR) genes, and pleiotropic effects on various neural crest (NC) genes. Because the affected embryonic structures give rise to several of the cranial tissues affected in Branchio-otic/Branchio-oto-renal (BOR) syndrome, herein we tested whether these gene expression changes subsequently alter the development of the proximate precursors of BOR affected structures - the otic vesicles (OV) and branchial arches (BA). We found that Mcrs1 is required for the expression of several OV genes involved in inner ear formation, patterning and otic capsule cartilage formation. Mcrs1 knockdown also reduced the expression domains of many genes expressed in the larval BA, derived from either NC or PPR, except for emx2, which was expanded. Reduced Mcrs1 also diminished the length of the expression domain of tbx1 in BA1 and BA2 and interfered with cranial NC migration from the dorsal neural tube; this subsequently resulted in defects in the morphology of lower jaw cartilages derived from BA1 and BA2, including the infrarostral, Meckel's, and ceratohyal as well as the otic capsule. These results demonstrate that Mcrs1 plays an important role in processes that lead to the formation of craniofacial cartilages and its loss results in phenotypes consistent with reduced Six1 activity associated with BOR., Competing Interests: Declaration of competing interest The authors declare that they do not have any conflicting financial or personal relationships that inappropriately influenced this work. The work described herein has not been previously published and is not under consideration for publication elsewhere., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Branchio-oto-renal syndrome is an autosomal dominant disorder characterized by branchial anomalies, hearing loss, and renal urinary tract malformations. We herein report a 32-year-old Japanese man with a right preauricular pit, bilateral mixed hearing loss, and malposition of the right kidney who presented with proteinuria. The findings of a left kidney biopsy were compatible with a perihilar variant of secondary focal segmental glomerular sclerosis. A trio exome analysis conducted among the patient and his parents failed to identify the causal gene variant, despite a sporadic pattern. His kidney function remained stable for 11 years with an angiotensin II receptor blocker.

Otofaciocervical syndrome (OTFCS) is a rare condition associated with short stature, abnormal facial features and conductive hearing loss. OTFCS type 2 (OTFCS) is an autosomal recessive form of this condition with associated T cell deficiency due to biallelic variants in PAX1. We report a female child born to a consanguineous couple with homozygous PAX1 variant. She was diagnosed with T cell immunodeficiency as a neonate and underwent haematopoietic stem cell transplant with cord blood at the age of 5 months. She had facial dysmorphism including ear abnormalities and spinal deformity. We present longitudinal follow-up of the proband who has responded well to the bone marrow transplant to add to the otherwise limited description of this rare condition. This case report expands on the limited literature available on this condition, with only five families reported to date and it further highlights the clinical utility of a rapid gene-agnostic trio exome analysis in identifying a genetic diagnosis in patients who previously underwent genomic testing by gene panel analysis., (Crown Copyright © 2022. Published by Elsevier Masson SAS. All rights reserved.)

Background and Purpose: Temporal bone imaging plays an important role in the work-up of branchio-oto-renal syndrome. Previous reports have suggested that the unwound or offset cochlea is a highly characteristic marker for branchio-oto-renal syndrome. Our goals were to examine the prevalence of this finding in a branchio-oto-renal syndrome cohort and analyze genetic-phenotypic associations not previously established., Materials and Methods: This multicenter retrospective study included 38 ears in 19 unrelated individuals with clinically diagnosed branchio-oto-renal syndrome and confirmed mutations in the EYA1 or SIX1 genes. Two blinded neuroradiologists independently reviewed and documented temporal bone imaging findings in 13 categories for each ear. Imaging phenotypes were correlated with genotypes., Results: There was excellent interrater agreement for all 13 phenotypic categories (κ ≥ 0.80). Of these, 9 categories showed statistically significant differences between patients with EYA1 -branchio-oto-renal syndrome and SIX1 -branchio-oto-renal syndrome. Cochlear offset was present in 100% of patients with EYA1 -branchio-oto-renal syndrome, but in only 1 ear (12.5%) among patients with SIX1 -branchio-oto-renal syndrome. A short thorny appearance of the cochlear apical turn was observed in most patients with SIX1 -branchio-oto-renal syndrome., Conclusions: An offset cochlea is associated with the EYA1 -branchio-oto-renal syndrome genotype. The SIX1 -branchio-oto-renal syndrome genotype is associated with a different cochlear phenotype that almost always is without offset and has a short thorny tip as the apical turn. Therefore, cochlear offset is not a characteristic marker for all patients with branchio-oto-renal syndrome. The lack of a cochlear offset in a patient with clinically suspected branchio-oto-renal syndrome does not exclude the diagnosis and, in fact, may be predictive of the SIX1 genotype., (© 2022 by American Journal of Neuroradiology.)

Branchio-oto syndrome (BOS)/branchio-oto-renal syndrome (BORS) is a kind of autosomal dominant heterogeneous disorder. These diseases are mainly characterized by hearing impairment and abnormal phenotype of ears, accompanied by renal malformation and branchial cleft anomalies including cyst or fistula, with an incidence of 1/40 000 in human population. Otic anormalies are one of the most obvious clinical manifestations of BOS/BORS, including deformities of external, middle, inner ears and hearing loss with conductive, sensorineural or mix, ranging from mild to profound loss. Temporal bone imaging could assist in the diagnosis of middle ear and inner ear malformations for clinicians. Multiple methods including direct sequencing combined with next generation sequencing (NGS), multiplex ligation-dependent probe amplification (MLPA), or array-based comparative genomic hybridization (aCGH) can effectively screen and identify pathogenic genes and/or variation types of BOS/BORS. About 40% of patients with BOS/BORS carry aberrations of EYA1 gene which is the most important cause of BOS/BORS. A total of 240 kinds of pathogenic variations of EYA1 have been reported in different populations so far, including frameshift, nonsense, missense, aberrant splicing, deletion and complex rearrangements. Human Endogenous Retroviral sequences (HERVs) may play an important role in mediating EYA1 chromosomal fragment deletion mutations caused by non-allelic homologous recombination. EYA1 encodes a phosphatase-transactivator cooperated with transcription factors of SIX1 , participates in cranial sensory neurogenesis and development of branchial arch-derived organs, then regulates the morphological and functional differentiation of the outer ear, middle ear and inner ear toward normal tissues. In addition, pathogenic mutations of SIX1 and SIX5 genes can also cause BOS/BORS. Variations of these genes mentioned above may cause disease by destroying the bindings between SIX1-EYA1, SIX5-EYA1 or SIX1-DNA. However, the role of SIX5 gene in the pathogenesis of BORS needs further verification.

Some patients have an atypical form of branchio-oto-renal (BOR) syndrome, which does not satisfy the diagnostic criteria, despite carrying a pathogenic variant (P variant) or a likely pathogenic variant (LP variant) of a causative gene. P/LP variants phenotypic indices have yet to be determined in patients with typical and atypical BOR syndrome. We hypothesized that determining phenotypic and genetic differences between patients with typical and atypical BOR syndrome could inform such indices. Subjects were selected from among patients who underwent genetic testing to identify the cause of hearing loss. Patients were considered atypical when they had two major BOR diagnostic criteria, or two major criteria and one minor criterion; 22 typical and 16 atypical patients from 35 families were included. Genetic analysis of EYA1, SIX1, and SIX5 was conducted by direct sequencing and multiplex ligation-dependent probe amplification. EYA1 P/LP variants were detected in 25% and 86% of atypical and typical patients, respectively. Four EYA1 P/LP variants were novel. Branchial anomaly, inner ear anomaly, and mixed hearing loss were correlated with P/LP variants. Development of refined diagnostic criteria and phenotypic indices for atypical BOR syndrome will assist in effective detection of patients with P/LP variants among those with suspected BOR syndrome., (© 2022. The Author(s).)

The vertebrate Six (Sine oculis homeobox) family of homeodomain transcription factors plays critical roles in the development of several organs. Six1 plays a central role in cranial placode development, including the precursor tissues of the inner ear, as well as other cranial sensory organs and the kidney. In humans, mutations in SIX1 underlie some cases of Branchio-oto-renal (BOR) syndrome, which is characterized by moderate-to-severe hearing loss. We utilized CRISPR/Cas9 technology to establish a six1 mutant line in Xenopus tropicalis that is available to the research community. We demonstrate that at larval stages, the six1-null animals show severe disruptions in gene expression of putative Six1 target genes in the otic vesicle, cranial ganglia, branchial arch, and neural tube. At tadpole stages, six1-null animals display dysmorphic Meckel's, ceratohyal, and otic capsule cartilage morphology. This mutant line will be of value for the study of the development of several organs as well as congenital syndromes that involve these tissues., (© 2021 Wiley Periodicals LLC.)

Objective: To analyze the clinical manifestations of a patient with branchiootic syndrome(BOS) and her families and to carry out genetic testing in order to specify the biological pathogenesis. Methods: Clinical data of the patient and her families were collected. Genomic DNA in the peripheral blood of the proband and her family members was extracted. All exons of 406 deafness-related susceptible genes as well as their flanking regions were sequenced by high-throughput sequencing, and the mutation sites of the proband and her parents were validated by Sanger sequencing. Results: There were nine members in three generations, of whom four presented with hearing loss, preauricular fistula and branchial fistula which met the diagnostic criteria of BOS. Proband and her mother presented with auricle malformation and inner ear malformation. And no one had abnormalities in the kidneys of all the patients. Pedigree analysis revealed that the mode of inheritance in the family was consistent with the autosomal dominant pattern. Mutational analysis showed that all the affected patients detected a heterozygous frameshift variation c.1255delT in the EYA1 gene, which had not been reported. Genotype and phenotype were co-isolated in this family. Such a frameshift variation produced a premature termination codon, thereby causing premature termination of translation (p.C419VFS*12). ACMG identified that the mutation was pathogenic. This mutation was novel and not detected in controls. A heterozygous missense variation mutation c.403G>A(p.G135S) in EYA1 gene was also detected in three members of this family. ACMG identified that the mutation clinical significance was uncertain. However, two of whom were normal, which seemed the disease was not caused by this mutation in this family. Conclusions: A novel frameshift mutation in EYA1 (c.1255delT) is the main molecular etiology of BOS in the Chinese family. This study expands the mutational spectrum of EYA1 gene. The clinical manifestations are heterogeneous among patients in this family. The diagnosis of BOS should combine gene tests with clinical phenotypes analysis.

Branchio-oto-renal syndrome (BOR) is a disorder characterized by hearing loss, and craniofacial and/or renal defects. Variants in the transcription factor Six1 and its co-factor Eya1, both of which are required for otic development, are linked to BOR. We previously identified Sobp as a potential Six1 co-factor, and SOBP variants in mouse and humans cause otic phenotypes; therefore, we asked whether Sobp interacts with Six1 and thereby may contribute to BOR. Co-immunoprecipitation and immunofluorescence experiments demonstrate that Sobp binds to and colocalizes with Six1 in the cell nucleus. Luciferase assays show that Sobp interferes with the transcriptional activation of Six1+Eya1 target genes. Experiments in Xenopus embryos that either knock down or increase expression of Sobp show that it is required for formation of ectodermal domains at neural plate stages. In addition, altering Sobp levels disrupts otic vesicle development and causes craniofacial cartilage defects. Expression of Xenopus Sobp containing the human variant disrupts the pre-placodal ectoderm similar to full-length Sobp, but other changes are distinct. These results indicate that Sobp modifies Six1 function and is required for vertebrate craniofacial development, and identify Sobp as a potential candidate gene for BOR., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)

Branchiootorenal spectrum disorder (BORSD) is a group of rare autosomal dominant entities characterized by branchiogenic malformations, hearing loss (HL) and renal anomalies. It comprises branchiootorenal syndrome and branchiootic syndrome, distinguished by the presence or absence of renal abnormalities. Pathogenic variants have been discovered in the following genes: EYA1, SIX5, SIX1 and SALL1. As the otological phenotype in BORSD is inconsistently reported, we performed a systematic review to provide an up-to-date overview, correlated with the genotype. Forty publications were included, describing 295 individual patients. HL was diagnosed in 95%, usually bilateral and mixed-type, and differed among the different genes involved. Mixed moderate-to-severe HL was the predominant finding in patients with EYA1 involvement, regardless of the presence of renal abnormalities. The sensorineural HL of profound severity was more prevalent in patients with SIX1 mutations. No significant differences among different mutation types or location within the genes could be observed. Structural otological manifestations, ranging from periauricular to inner ear anomalies, were common in both genes. Especially periauricular anomalies were more common and more severe in EYA1. In summary, otological differences among the different genes involved in BORSD are observed, so the molecular analysis is strongly advised., (© 2021 John Wiley & Sons A/S . Published by John Wiley & Sons Ltd.)

Objective: To identify novel genetic causes of branchio-oto-renal （BOR） syndrome in a Chinese family. Methods: Clinical characteristics and treatment of a family with a BOR syndrome were retrospectively analyzed. Genetic analysis was conducted by trio whole exome sequencing （WES） and the duplicated exons were verified by fluorescence quantitative PCR （real-time PCR）. Results: In this family, the affected individual had deafness, structural malformation of inner ear and middle ear, pre-auricular fistula, cervical fistula and renal atrophy consistent with the clinical diagnosis of BOR syndrome. Neither the father nor the mother had similar phenotype. WES and quantitative fluorescent PCR revealed that the patient had a de novo partial duplication involving exons 13 to 18 of EYA1 gene. This mutation has not been reported in literature or any database. Bilateral pre-auricular fistulas and cervical fistulas were surgically removed and the surgery wound healed well, while hearing AIDS had been worn to assist hearing. Conclusion: This study is the first to detect a novel de novo partial duplication （exons13-18） of EYA1 gene leading to BOR syndrome, and expands the mutant spectrum of EYA1 gene in Chinese population., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

Abstract: Branchio-Oto (BO) syndrome is one of the common syndromic forms of hearing loss. In this study, we aimed to characterize the clinical and genetic features of BO syndrome in a Chinese deaf family.The proposita in this study was a 29-years-old Chinese female with hearing loss, microtia, anterior concave auricle, and right branchial fistula. The family members agreed to undergo clinical examination. We collected blood samples from 7 family members, including 4 affected by the syndrome. Genomic DNA was extracted and subjected to Sanger sequencing. In addition, bioinformatics software SWISS MODEL was used to predict the protein encoded by EYA transcriptional coactivator and phosphatase 1 (EYA1) gene.Intra-familial consistency can be observed in the clinical phenotypes of BO syndrome in this family. EYA1 c.1627C>T (p.Gln543Ter) mutation was identified as the pathogenic cause in this family.This study reports a mutation associated with BO syndrome in a Chinese Han family. We highlight the utility of genetic testing in the diagnosis of BO syndrome. Thus, we believe that this report would provide a basis for the diagnosis of similar diseases in the future., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Branchio-oto-renal spectrum disorder (BORSD) is characterized by hearing loss accompanied by ear malformations, branchial cysts, and fistulae, with (branchio-oto-renal syndrome (BORS)) or without renal abnormalities (BOS (branchio-otic syndrome)). As the most common causative gene for BORSD, dominant mutations in EYA1 are responsible for approximately 40% of the cases. In a sporadic deaf patient diagnosed as BOS, we identified an apparent heterozygous genomic deletion spanning the first four coding exons and one 5' noncoding exon of EYA1 by targeted next-generation sequencing of 406 known deafness genes. Real-time PCR at multiple regions of EYA1 confirmed the existence of this genomic deletion and extended its 5' boundary beyond the 5'-UTR. Whole genome sequencing subsequently located the 5' and 3' breakpoints to 19268 bp upstream to the ATG initiation codon and 3180 bp downstream to exon 5. PCR amplification across the breakpoints in both the patient and his parents showed that the genomic alteration occurred de novo . Sanger sequencing of this PCR product revealed that it is in fact a GRCh38/hg38:chr8:g.71318554&#95;71374171delinsTGCC genomic deletion-insertion. Our results showed that the genomic variant is responsible for the hearing loss associated with BOS and provided an example for deciphering such cryptic genomic alterations following pipelines of comprehensive exome/genome sequencing and designed verification., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Hao Zheng et al.)

Objective: To evaluate the genotype-phenotype correlation of branchio-otic syndrome (BOS) in a Chinese family., Methods: The proband in this study was an 18-month-old boy with hearing loss, preauricular pit, and branchial fistula without a renal anomaly. We collected blood samples from 6 family members, including 4 who were affected by the syndrome. Targeted next-generation sequencing and Sanger sequencing were performed to identify pathogenic mutations in this family., Results: Pedigree analysis indicated that the mode of inheritance in the family was consistent with the autosomal dominant pattern. Hearing loss was the most common manifestation, occurring in 4 patients. Other findings included preauricular pits (n=2), cervical fistulas (n=3) and abnormal pinnae (n=4). None of the patients had renal anomalies. Evaluation by pure-tone audiometry and temporal bone imaging demonstrated bilateral mixed hearing loss, as well as middle ear and inner ear deformities, in two patients. Mutational analysis of candidate genes in the selected patients led to the identification of a novel frameshift variant NM&#95;000503.4: c.1075&#95;1077delinsAT (p.Gly359Ilefs*7) in the EYA1 gene., Conclusions: The EYA1 c.1075&#95;1077delinsAT mutation is the causative variant in the Chinese family with BOS, although the penetrance is variable within patients., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Branchial cleft abnormality is a common congenital neck malformation in children, which is caused by the abnormal development of the gill sac or gill groove. It is mainly manifested as a cyst in the sinus tract and fistula in the neck, as well as branchio-oto-renal syndrome (BORS). As a rare autosomal dominant genetic disease, the typical manifestations of BORS are hearing loss, abnormal branchial cleft development and renal dysplasia. In this paper, a patient was admitted to the hospital for bilateral branchial cleft fistulas combined with bilateral anterior auricular fistulas, auricular appendix, auricle dysplasia, external auditory canal stenosis, and hearing loss. The patient was diagnosed with BORS, and underwent fistulectomy of the neck and anterior ear, external auditory canal formation, and tympanoplasty. The aim of this report is to strengthen clinicians' understanding of BORS and reduce the rate of clinical missed diagnosis through our case report and literature review.

The synchronized advent of high-throughput next-generation sequencing technology and knowledge of the human genome has rendered exponential contributions to our understanding of the pathophysiology of glomerular kidney diseases. A genetic diagnosis can now be made or confirmed in about two-thirds of the suspected inherited glomerular diseases. Next-generation sequencing is adept at identifying single nucleotide variations and small insertions or deletions that constitute majority of the disease-causing mutations. Description of the complete mutation spectrum in syndromic glomerulopathies may require the use of both sequencing and cytogenetic methods to detect large structural DNA variation in addition to single nucleotide changes. The enthusiastic application of genetic and genomic knowledge to inherited glomerular diseases has uncovered anticipated and unforeseen challenges mainly related to the biological interpretation of variants of uncertain significance and the limited benefit on clinical management for the individual patient when a diagnosis is obtained. To attain the ultimate goal of transforming clinical decision-making based on accurate genetic diagnosis using genomic information, these challenges need to be addressed. Till then, the glory of genomic medicine stands the test of time in this gilded age of genomic advancements.

22q11.2 deletion syndrome (DiGeorge), CHARGE syndrome, Nude/SCID and otofaciocervical syndrome type 2 (OTFCS2) are distinct clinical conditions in humans that can result in hypoplasia and occasionally, aplasia of the thymus. Thymic hypoplasia/aplasia is first suggested by absence or significantly reduced numbers of recent thymic emigrants, revealed in standard-of-care newborn screens for T cell receptor excision circles (TRECs). Subsequent clinical assessments will often indicate whether genetic mutations are causal to the low T cell output from the thymus. However, the molecular mechanisms leading to the thymic hypoplasia/aplasia in diverse human syndromes are not fully understood, partly because the problems of the thymus originate during embryogenesis. Rodent and Zebrafish models of these clinical syndromes have been used to better define the underlying basis of the clinical presentations. Results from these animal models are uncovering contributions of different cell types in the specification, differentiation, and expansion of the thymus. Cell populations such as epithelial cells, mesenchymal cells, endothelial cells, and thymocytes are variably affected depending on the human syndrome responsible for the thymic hypoplasia. In the current review, findings from the diverse animal models will be described in relation to the clinical phenotypes. Importantly, these results are suggesting new strategies for regenerating thymic tissue in patients with distinct congenital disorders., (Copyright © 2020 Bhalla, Wysocki and van Oers.)

Single-nucleotide mutations in human SIX1 result in amino acid substitutions in either the protein-protein interaction domain or the homeodomain, and cause ∼4% of branchio-otic (BOS) and branchio-oto-renal (BOR) cases. The phenotypic variation between patients with the same mutation, even within affected members of the same family, make it difficult to functionally distinguish between the different SIX1 mutations. We made four of the BOS/BOR substitutions in the Xenopus Six1 protein (V17E, R110W, W122R, Y129C), which is 100% identical to human in both the protein-protein interaction domain and the homeodomain, and expressed them in embryos to determine whether they cause differential changes in early craniofacial gene expression, otic gene expression or otic morphology. We confirmed that, similar to the human mutants, all four mutant Xenopus Six1 proteins access the nucleus but are transcriptionally deficient. Analysis of craniofacial gene expression showed that each mutant causes specific, often different and highly variable disruptions in the size of the domains of neural border zone, neural crest and pre-placodal ectoderm genes. Each mutant also had differential effects on genes that pattern the otic vesicle. Assessment of the tadpole inner ear demonstrated that while the auditory and vestibular structures formed, the volume of the otic cartilaginous capsule, otoliths, lumen and a subset of the hair cell-containing sensory patches were reduced. This detailed description of the effects of BOS/BOR-associated SIX1 mutations in the embryo indicates that each causes subtle changes in gene expression in the embryonic ectoderm and otocyst, leading to inner ear morphological anomalies., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2020. Published by The Company of Biologists Ltd.)

We investigated the molecular and cellular basis of severe combined immunodeficiency (SCID) in six patients with otofaciocervical syndrome type 2 who failed to attain T cell reconstitution after allogeneic hematopoietic stem cell transplantation, despite successful engraftment in three of them. We identified rare biallelic PAX1 rare variants in all patients. We demonstrated that these mutant PAX1 proteins have an altered conformation and flexibility of the paired box domain and reduced transcriptional activity. We generated patient-derived induced pluripotent stem cells and differentiated them into thymic epithelial progenitor cells and found that they have an altered transcriptional profile, including for genes involved in the development of the thymus and other tissues derived from pharyngeal pouches. These results identify biallelic, loss-of-function PAX1 mutations as the cause of a syndromic form of SCID due to altered thymus development., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Objectives: Branchio-oto-renal (BOR) syndrome is characterized by branchial defects, hearing loss, preauricular pits, and renal anomalies, whereas patients with all symptoms except renal defects are diagnosed as branchio-oto (BO) syndrome. BOR/BO is one of the most common forms of autosomal dominant syndromic hearing loss, and EYA1 is the major causative gene. In this study, clinical and genetic analyses as well as auditory rehabilitation were performed in a Chinese family with BOR/BO syndrome., Methods: Three affected individuals from a Chinese family were analyzed by whole exome sequencing (WES) to analyze the single nucleotide variants and copy number variations (CNVs). Whole genome sequencing was used to identify the breakpoints of CNVs; and quantitative polymerase chain reaction was utilized to verify the CNVs. Furthermore, cochlea implantation was performed in one patient to reconstruct hearing., Results: A heterozygous 2.69 Mb deletion at chromosome 8q13 (chr8: 69582185-72275725) cosegregates with the BOR/BO symptoms in this family, resulting in heterozygous loss of the EYA1 gene. In addition to typical BOR/BO symptoms, epilepsy or gastroesophageal reflux was observed in some patients. Cochlear implantation resulted in significant hearing improvement in one patient., Conclusions: A novel deletion involving the whole EYA1 gene was identified by WES. To the best of our knowledge, epilepsy or gastroesophageal reflux was reported in BOR/BO patients for the first time, which expanded the BOR/BO phenotypes spectrum. Successful auditory rehabilitation can be achieved with cochlear implantations in some BOR/BO patients., Level of Evidence: 4 Laryngoscope, 130:526-532, 2020., (© 2019 The American Laryngological, Rhinological and Otological Society, Inc.)

Objective: To carry out prenatal diagnosis for a women with Branchio-oto-renal syndrome by using chromosomal microarray analysis (CMA)., Methods: Peripheral blood chromosomal karyotyping and CMA were used to analyze the gravida with an abnormal phenotype. Pathological copy number variants (CNVs) were validated in other members of the family members and her fetus., Results: The gravida and her daughter both had Branchio-oto-renal syndrome and a 8q13.3 microdeletion encompassing the EYA1 gene. The same microdeletion was also found in the fetus. No phenotypic or genotypic anomaly was found with other members of the family., Conclusion: Mutation of the EYA1 gene probably underlies the Branchio-oto-renal syndrome in this family, which is consistent with an autosomal dominant inheritance.

Objectives: Branchio-Oto (BO) syndrome is one of the common syndromic forms of hearing loss. In this study, we aimed to characterize the clinical and genetic features of BO syndrome in two Chinese Han deaf families., Methods: The auditory and other BO-related clinical features of Family 1809 and Family 1974 were summarized. Targeted next-generation sequencing in 144 known deafness genes was performed in the probands. Co-segregation of the pathogenic mutations and the phenotype was confirmed by Sanger sequencing in the family members., Results: Interfamilial and intrafamilial variations can be observed in the clinical phenotypes of BO syndrome in Family 1809 and 1974. A novel c.1493&#95;1494insAT (p.Ile498PhefsTer*3) mutation and a previous reported c.967-2A>G mutation in EYA1 were identified as the pathogenic cause in Family 1974 and 1809, respectively., Conclusion: Our results supported the heterogeneity of the genetic and phenotypic spectrum of BO syndrome. The recurrent c.967-2A>G in different ethnical groups suggested that it is a hot-spot mutation., (Copyright © 2019. Published by Elsevier B.V.)

We report 3 siblings with brachio-oculo-facial syndrome (BOFS) who present with the predominant ocular phenotype. This syndrome has rarely been reported in multiple first-degree relatives., (Copyright © 2019 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

The pathological consequences of structural variants disrupting 3D genome organization can be difficult to elucidate in vivo due to differences in gene dosage sensitivity between mice and humans. This is illustrated by branchiooculofacial syndrome (BOFS), a rare congenital disorder caused by heterozygous mutations within TFAP2A, a neural crest regulator for which humans, but not mice, are haploinsufficient. Here, we present a BOFS patient carrying a heterozygous inversion with one breakpoint located within a topologically associating domain (TAD) containing enhancers essential for TFAP2A expression in human neural crest cells (hNCCs). Using patient-specific hiPSCs, we show that, although the inversion shuffles the TFAP2A hNCC enhancers with novel genes within the same TAD, this does not result in enhancer adoption. Instead, the inversion disconnects one TFAP2A allele from its cognate enhancers, leading to monoallelic and haploinsufficient TFAP2A expression in patient hNCCs. Our work illustrates the power of hiPSC differentiation to unveil long-range pathomechanisms., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Branchio-oto-renal (BOR) syndrome is one of the most common autosomal dominant hearing loss syndromes and features clinical and genetic heterogeneity. When there is no renal deformity, this disease can also be called branchio-otic (BO) syndrome. Though many genes have been reported, there are still many BO syndrome-related genes to be identified. To identify a hitherto unknown candidate gene causing BO syndrome in a three-generation Chinese family, clinical, genetic, and functional analyses were employed., Methods: Whole-exome sequencing (WES) was conducted in three affected family members and two unaffected family members. PCR-Sanger sequencing was performed in all of the family members for segregation analysis and verification of the candidate variants. PCR-Sanger sequencing was also employed in 150 healthy people to examine the variants. In silico analysis was used to predict possible changes in the protein structure that may affect the phenotype., Results: We identified a heterozygous missense variant in ANLN: NM&#95;018685.4: c.G1105A; NP&#95;061155.2: p.G369R that segregated in the pedigree with an autosomal dominant pattern. No variant was found in the 150 controls and normal family members at this site. The variant c.G1105A was located in a highly conserved F-actin binding site. The amino acid residue at position 369 in the ANLN protein was highly conserved across different species., Conclusion: In this study, we identified, for the first time, a heterozygous missense variant in ANLN (NM&#95;018685.4: c.G1105A; NP&#95;061155.2: p.G369R) that is likely to be a candidate causative gene of BO syndrome in a specific Chinese family., (© 2018 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.)

Background: Branchio-oto-renal (BOR) syndrome is a dominant autosomal disorder characterized by phenotypes such as hearing loss, branchial fistulae, preauricular pits, and renal abnormalities. EYA1, the human homolog of the Drosophila "eye absent" gene on chromosome 8q13.3, is recognized as one of the most important genes associated with BOR syndrome., Methods: The proposita in this study was a 5-year-old Chinese girl with hearing loss, bilateral otitis media with effusion, microtia, facial hypoplasia, palatoschisis, and bilateral branchial cleft fistulae. The girl's family members, except two who were deceased, agreed to undergo clinical examination. We collected blood samples from 10 family members, including six who were affected by the syndrome. Genomic DNA was extracted and subjected to Sanger sequencing. A minigene assay was performed to confirm whether splicing signals were altered. In addition, we performed western blotting to determine alterations in protein levels of the wild-type and mutant gene., Results: Clinical tests showed that some of the family members met the criteria for BOR syndrome. The affected members harbored a novel heterozygous nonsense variation in exon 11 of EYA1, whereas no unaffected member carried the mutation at this position. Functional experiments did not detect abnormal splicing at the RNA level; however, western blotting showed that the mutated protein was truncated., Conclusions: This study reports a novel mutation associated with BOR syndrome in a Chinese family. We highlight the usefulness of genetic testing in the diagnosis of BOR syndrome. Thus, we believe that this report would benefit clinicians in this field.

Objectives: The aim of this study is to define the candidate target genes for TFII-I and AP2α regulation in neural crest progenitor cells., Design: The GTF2I and GTF2IRD1 genes encoding the TFII-I family of transcription factors are prime candidates for the Williams-Beuren syndrome, a complex multisystem disorder characterized by craniofacial, skeletal, and neurocognitive deficiencies. AP2α, a product of the TFAP2A gene, is a master regulator of neural crest cell lineage. Mutations in TFAP2A cause branchio-oculo-facial syndrome characterized by dysmorphic facial features and orofacial clefts. In this study, we examined the genome-wide promoter occupancy of TFII-I and AP2α in neural crest progenitor cells derived from in vitro-differentiated human embryonic stem cells., Results: Our study revealed that TFII-I and AP2α co-occupy a selective set of genes that control the specification of neural crest cells., Conclusions: The data suggest that TFII-I and AP2α may coordinately control the expression of genes encoding chromatin-modifying proteins, epigenetic enzymes, transcription factors, and signaling proteins.

Otofaciocervical syndrome (OTFCS) is described as a single gene disorder of both autosomal dominant and autosomal recessive inheritance. The major clinical features of OTFCS include ear malformations (external/middle/inner ear), facial dysmorphism, shoulder girdle abnormalities, vertebral anomalies, and mild intellectual disability. The autosomal recessive form of OTFCS syndrome (OTFCS2) has been recently reported to be caused due to homozygous mutations in PAX1 gene. Here we report a third family of OTFCS2 phenotype wherein whole exome sequencing identified a novel homozygous small insertion in PAX1 as the underlying genetic cause., (© 2018 Wiley Periodicals, Inc.)