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The blood-brain barrier (BBB) is an essential gatekeeper for the central nervous system and incidence of neurodevelopmental disorders (NDDs) is higher in infants with a history of intracerebral hemorrhage (ICH). We discovered a rare disease trait in thirteen individuals, including four fetuses, from eight unrelated families associated with homozygous loss-of-function variant alleles of ESAM which encodes an endothelial cell adhesion molecule. The c.115del (p.Arg39Glyfs∗33) variant, identified in six individuals from four independent families of Southeastern Anatolia, severely impaired the in vitro tubulogenic process of endothelial colony-forming cells, recapitulating previous evidence in null mice, and caused lack of ESAM expression in the capillary endothelial cells of damaged brain. Affected individuals with bi-allelic ESAM variants showed profound global developmental delay/unspecified intellectual disability, epilepsy, absent or severely delayed speech, varying degrees of spasticity, ventriculomegaly, and ICH/cerebral calcifications, the latter being also observed in the fetuses. Phenotypic traits observed in individuals with bi-allelic ESAM variants overlap very closely with other known conditions characterized by endothelial dysfunction due to mutation of genes encoding tight junction molecules. Our findings emphasize the role of brain endothelial dysfunction in NDDs and contribute to the expansion of an emerging group of diseases that we propose to rename as “tightjunctionopathies.”

Non-centrosomal microtubules are essential cytoskeletal filaments that are important for neurite formation, axonal transport, and neuronal migration. They require stabilization by microtubule minus-end-targeting proteins including the CAMSAP family of molecules. Using exome sequencing on samples from five unrelated families, we show that bi-allelic CAMSAP1 loss-of-function variants cause a clinically recognizable, syndromic neuronal migration disorder. The cardinal clinical features of the syndrome include a characteristic craniofacial appearance, primary microcephaly, severe neurodevelopmental delay, cortical visual impairment, and seizures. The neuroradiological phenotype comprises a highly recognizable combination of classic lissencephaly with a posterior more severe than anterior gradient similar to PAFAH1B1(LIS1)-related lissencephaly and severe hypoplasia or absence of the corpus callosum; dysplasia of the basal ganglia, hippocampus, and midbrain; and cerebellar hypodysplasia, similar to the tubulinopathies, a group of monogenic tubulin-associated disorders of cortical dysgenesis. Neural cell rosette lineages derived from affected individuals displayed findings consistent with these phenotypes, including abnormal morphology, decreased cell proliferation, and neuronal differentiation. Camsap1-null mice displayed increased perinatal mortality, and RNAScope studies identified high expression levels in the brain throughout neurogenesis and in facial structures, consistent with the mouse and human neurodevelopmental and craniofacial phenotypes. Together our findings confirm a fundamental role of CAMSAP1 in neuronal migration and brain development and define bi-allelic variants as a cause of a clinically distinct neurodevelopmental disorder in humans and mice.

Rhizomelic chondrodysplasia punctata (RCDP) are a group of peroxisomal disorders caused by plasmalogen synthesis defects. Patients with RCDP present with rhizomelic short stature, characteristic punctate epiphyseal calcifications, congenital cataracts, severe intellectual disability, seizures, and facial dysmorphism. Pathogenic variants in AGPS result in RCDP type 3 (RCDP3) which is an extremely rare disorder characterized by isolated ADHAPS deficiency. Six patients with RCDP3 have been identified, upto-date. We report two new patients with RCDP3 and their novel variants, c.154dupG (p.Ala52GlyfsTer6) and c.637+1GA, in the AGPS gene. We also present a review of previously reported RCDP3 patients.

Background: Maturity-onset diabetes of the young (MODY), which is the most common cause of monogenic diabetes, has an autosomal dominant pattern of inheritance and exhibits marked clinical and genetic heterogeneity. The aim of the current study was to investigate molecular defects in patients with clinically suspected MODY using a next-generation sequencing (NGS)-based targeted gene panel. Methods: Candidate patients with clinical suspicion of MODY and their parents were included in the study. Molecular genetic analyses were performed on genomic DNA by using NGS. A panel of ten MODY-causal genes involving GCK, HNF1A, HNF1B, HNF4A, ABCC8, CEL, INS, KCNJ11, NEUROD1, PDX1 was designed and subsequently implemented to screen 40 patients for genetic variants. Results: Ten different pathogenic or likely pathogenic variants were identified in MODY-suspected patients, with a diagnostic rate of 25%. Three variants of uncertain significance were also detected in the same screen. A novel pathogenic variant in the gene HNF1A (c.505_506delAA [p.Lys169AlafsTer18]) was described for the first time in this report. Intriguingly, we were able to detect variants associated with rare forms of MODY in our study population. Conclusions: Our results suggest that in heterogenous diseases such as MODY, NGS analysis enables accurate identification of underlying molecular defects in a timely and cost-effective manner. Although MODY accounts for 2-5% of all diabetic cases, molecular genetic diagnosis of MODY is necessary for optimal long-term treatment and prognosis as well as for effective genetic counseling.

Background Although the underlying genetic causes of intellectual disability (ID) continue to be rapidly identified, the biological pathways and processes that could be targets for a potential molecular therapy are not yet known. This study aimed to identify ID-related shared pathways and processes utilizing enrichment analyses. Method In this multicenter study, causative genes of patients with ID were used as input for Disease Ontology (DO), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. Results Genetic test results of 720 patients from 27 centers were obtained. Patients with chromosomal deletion/duplication, non-ID genes, novel genes, and results with changes in more than one gene were excluded. A total of 558 patients with 341 different causative genes were included in the study. Pathway-based enrichment analysis of the ID-related genes via ClusterProfiler revealed 18 shared pathways, with lysine degradation and nicotine addiction being the most common. The most common of the 25 overrepresented DO terms was ID. The most frequently overrepresented GO biological process, cellular component, and molecular function terms were regulation of membrane potential, ion channel complex, and voltage-gated ion channel activity/voltage-gated channel activity, respectively. Conclusion Lysine degradation, nicotine addiction, and thyroid hormone signaling pathways are well-suited to be research areas for the discovery of new targeted therapies in ID patients.

Amaç: Bu çalışmanın amacı, hastanemize infertilite nedeniyle başvuran erkeklere yardımcı üreme tekniklerinden önce uygun genetik danışmanlık verebilmek için, azospermi ve/veya oligozoospermi etiyolojisine yönelik standart sitogenetik yöntemler ve Y kromozom mikrodelesyon analizleri ile hem majör kromozom anomalilerinin hem de Y kromozomu mikrodelesyonlarının sıklığı ve tiplerini araştırmaktır. Gereç ve Yöntemler: Çalışmamıza 2017-2020 yılları arasında erkek infertilitesi nedeniyle Kanuni Sultan Süleyman Eğitim ve Araştırma hastanemize başvuran toplam 437 hasta dâhil edildi. Tüm hastalar spermiogram, hormonal profil, kromozom analizi ve Y mikrodelesyon analizleri doğrultusunda değerlendirildi. Bulgular: Çalışmamızda toplam 437 hastanın 42’sinde (%9,6) kromozomal anomaliler tespit edildi. En sık görülen kromozomal anomali 47,XXY(Klinefelter sendromu) idi. 5 hastamızda dengeli translokayonlar vardı. 1 hastada ise marker kromozom tespit edildi. Geriye kalan 395 hastanın kromozom analizi normaldi. 44 hastamızda (%10,06) ise AZF genleri üzerinde çeşitli y-kromozomu mikrodelesyonları saptandı. 1 hastada AZFa delesyonu, 4 hastada AZFb+c delesyonu, 17 hastada AZF-c gr/gr delesyonu, 2 hastada komplet AZFa+b+c delesyonu, 2 hastada komplet AZFc delesyonu, 1 hastada parsiyel AZFb delesyonu, 9 hastada kısmi AZFb+c delesyonu, 8 hastada parsiyel AZFc delesyonu tespit edildi. Geriye kalan 393 hastada herhangi bir Y kromozomu mikrodelesyonu saptanmadı. Sonuç: Mevcut bilgiler ve geçmişteki literatür çalışmaları eşliğinde özellikle şiddetli oligospermi ve azospermili hastalarda kromozom analizi ve Y mikro delesyonu analizlerini yardımcı üreme tekniklerinden önce önermekteyiz.

Introduction: Hereditary cholestasis is a heterogeneous group of liver diseases that mostly show autosomal recessive inheritance. The phenotype of cholestasis is highly variable. Molecular genetic testing offers an useful approach to differentiate different types of cholestasis because some symptoms and findings overlap. Biallelic variants in USP53 have recently been reported in cholestasis phenotype. Methods: In this study, we aimed to characterize clinical findings and biological insights on a novel USP53 splice variant causing cholestasis phenotype and provided a review of the literature. We performed whole-exome sequencing and then confirmed it with Sanger sequencing. In addition, as a result of in silico analyses and cDNA analysis, we showed that the USP53 protein in our patient was shortened. Results: We report a novel splice variant (NM_019050.2:c.238–1G>C) in the USP53 gene via whole-exome sequencing in a patient with cholestasis phenotype. This variant was confirmed by Sanger sequencing and was a result of family segregation analysis; it was found to be in a heterozygous state in the parents and the other healthy elder brother of our patient. According to in silico analyses, the change in the splice region resulted in an increase in the length of exon 2, whereas the stop codon after the additional 3 amino acids (VTF) caused the protein to terminate prematurely. Thus, the mature USP53 protein, consisting of 1,073 amino acids, has been reduced to a small protein of 82 amino acids. Conclusion: We propose a model for the tertiary structure of USP53 for the first time, and together with all these data, we support the association of biallelic variants of the USP53 gene with cholestasis phenotype. We also present a comparison of previously reported patients with USP53-associated cholestasis phenotype to contribute to the literature.

Objective: This study aimed to evaluate the effect of an increase in nuchal translucency (NT) thickness on the myocardial performance index (MPI) in fetuses without cardiac anomaly in the first trimester and to determine whether a difference in MPI between those with and without trisomy 21 in these fetuses could be determined. Methods: The study group consisted of 53 pregnancies complicated with increased NT thickness without any associated structural anomalies. Forty-six gestational age-matched pregnant women whose fetuses had normal NT thickness were enrolled as the control group. Results: In the increased NT thickness group, the mean isovolumetric relaxation time (IRT) value (0.050 ± 0.011 s) was significantly higher and the mean ejection time (ET) value (0.149 ± 0.010 s) was significantly lower than those values in the normal NT thickness group (0.045 ± 0.005 and 0.155 ± 0.009 s, p = 0.023 and p = 0.009, respectively). We found a significantly higher mean left MPI value in the increased NT thickness group (0.574 ± 0.153) versus the normal NT thickness group (0.487 ± 0.107, p < 0.001). Within the increased NT thickness group, the mean left MPI value was similar in the fetuses with normal karyotype and those with trisomy 21 (p = 0.419). Conclusion: We demonstrated a significantly greater mean MPI value in the increased NT thickness group than in the normal NT thickness group. Within the increased NT thickness group, no differences in the left MPI value in the fetuses with normal karyotype and the fetuses with trisomy 21 were found.

Protein phosphatase 1 regulatory subunit 35 (PPP1R35) encodes a centrosomal protein required for recruiting microtubule-binding elongation machinery. Several proteins in this centriole biogenesis pathway correspond to established primary microcephaly (MCPH) genes, and multiple model organism studies hypothesize PPP1R35 as a candidate MCPH gene. Here, using exome sequencing (ES) and family-based rare variant analyses, we report a homozygous, frameshifting indel deleting the canonical stop codon in the last exon of PPP1R35 [Chr7: c.753_*3delGGAAGCGTAGACCinsCG (p.Trp251Cysfs*22)]; the variant allele maps in a 3.7 Mb block of absence of heterozygosity (AOH) in a proband with severe MCPH (-4.3 SD at birth, -6.1 SD by 42 months), pachygyria, and global developmental delay from a consanguineous Turkish kindred. Droplet digital PCR (ddPCR) confirmed mutant mRNA expression in fibroblasts. In silico prediction of the translation of mutant PPP1R35 is expected to be elongated by 18 amino acids before encountering a downstream stop codon. This complex indel allele is absent in public databases (ClinVar, gnomAD, ARIC, 1000 genomes) and our in-house database of 14,000+ exomes including 1800+ Turkish exomes supporting predicted pathogenicity. Comprehensive literature searches for PPP1R35 variants yielded two probands affected with severe microcephaly (-15 SD and -12 SD) with the same homozygous indel from a single, consanguineous, Iranian family from a cohort of 404 predominantly Iranian families. The lack of heterozygous cases in two large cohorts representative of the genetic background of these two families decreased our suspicion of a founder allele and supports the contention of a recurrent mutation. We propose two potential secondary structure mutagenesis models for the origin of this variant allele mediated by hairpin formation between complementary GC rich segments flanking the stop codon via secondary structure mutagenesis.

Neurodevelopmental disorders (NDD5) are clinically and genetically heterogenous; many such disorders are secondary to perturbation in brain development and/or function. The prevalence of NDD5 is > 3%, resulting in significant sociocultural and economic challenges to society. With recent advances in family-based genomics, rare-variant analyses, and further exploration of the Clan Genomics hypothesis, there has been a logarithmic explosion in neurogenetic "disease-associated genes" molecular etiology and biology of NDD5; however, the majority of NDD5 remain molecularly undiagnosed. We applied genome-wide screening technologies, including exome sequencing (ES) and whole-genome sequencing (WGS), to identify the molecular etiology of 234 newly enrolled subjects and 20 previously unsolved Turkish NDD families. In 176 of the 234 studied families (75.2%), a plausible and genetically parsimonious molecular etiology was identified. Out of 176 solved families, deleterious variants were identified in 218 distinct genes, further documenting the enormous genetic heterogeneity and diverse perturbations in human biology underlying NDD5. We propose 86 candidate disease-trait-associated genes for an NDD phenotype. Importantly, on the basis of objective and internally established variant prioritization criteria, we identified 51 families (51/176 = 28.9%) with multilocus pathogenic variation (MPV), mostly driven by runs of homozygosity (ROH5) - reflecting genomic segments/haplotypes that are identical-by-descent. Furthermore, with the use of additional bioinformatic tools and expansion of ES to additional family members, we established a molecular diagnosis in 5 out of 20 families (25%) who remained undiagnosed in our previously studied NDD cohort emanating from Turkey. United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Human Genome Research Institute (NHGRI) ; United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Heart Lung & Blood Institute (NHLBI) ; International Rett Syndrome Foundation (IRSF

Children with Down syndrome have a high incidence of major malformations and corrective surgery. Some patients do not need any surgery, while some cases are operated for several indications. There are few studies investigating the effect of maternal age on the phenotype of these children, despite the fact that increasing maternal age is a known risk factor for giving birth to Down syndrome. We aimed to investigate the incidence of surgery for major malformations and disorders in children with Down syndrome and its relationship with maternal age at birth.We revised the records of 218 children with Down syndrome for maternal age at birth and for surgical interventions.There were 84 children who had at least one operation with 38.5% incidence. A total of 49 children had cardiac surgery, 16 had gastrointestinal, 17 had head and neck area, 12 had ophthalmological, 12 had genitourinary, 5 had hernia, and 2 had orthopedic surgeries. The mean maternal age was 32.7 (minimum: 15; maximum: 44), and there was no significant difference between operated and non-operated groups for mean maternal ages (32.41 and 32.93, respectively; p=0.89). For any type of surgery, there was no significant difference between the groups with maternal ages 35 and over and those under 35.Maternal age at birth has no effect on the incidence of malformations and the probability of operation in Down syndrome.Down sendromlu çocuklarda majör malformasyon ve düzeltici cerrahi insidansı yüksektir. Bazı olgular birden fazla endikasyon için ameliyat olurken, bazı hastalar ameliyat gerektiren bir sorun yaşamaz. Anne yaşının artması Down sendromlu çocuk doğurmak için bilinen bir risk faktörüdür, ancak anne yaşının bu çocukların fenotipi üzerindeki etkisini araştıran fazla çalışma yoktur. Çalışmamızda Down sendromlu çocuklarda majör malformasyon ameliyatlarının insidansını ve doğumdaki anne yaşı ile ilişkisini araştırmayı amaçladık.Down Sendromlu 218 çocuğun dosyalarını, doğumdaki anne yaşı ve cerrahi müdahaleler açısından retrospektif taradık.En az bir ameliyat geçiren çocuk sayısı 84, insidansı %38,5 idi. Çocukların 49’u kalp ameliyatı, 16’sı gastrointestinal, 17’si baş boyun bölgesi, 12’si göz, 12’si genitoüriner, 5’i fıtık ve 2’si ortopedik ameliyat geçirdi. Ortalama anne yaşı 32,7 (minimum: 15, maksimum: 44) idi ve opere olan ve olmayan gruplar arasında ortalama anne yaşı açısından anlamlı fark yoktu (sırasıyla 32,41 ve 32,93, p=0,89). Anne yaşı 35 ve üzeri olan ve 35 yaş altı olan gruplar arasında herhangi bir ameliyat türü açısından anlamlı fark bulunmadı.Down sendromlu çocuklarda en sık yapılan operasyonlar kalp, gastrointestinal ve baş boyun bölgesi operasyonlarıdır. Doğumda anne yaşının Down sendromunda malformasyon insidansı ve operasyon olasılığı üzerine etkisi izlenmemektedir.

Crisponi/cold-induced sweating syndrome (CS/CISS) is a rare autosomal recessive disorder characterized by episodic hyperthermia, arthrogryposis, impaired feeding ability, and respiratory distress. The classic CS/CISS is mainly associated with CRLF1 and, rarely, CLCF1. PERCHING syndrome, previously known as CS/CISS type-3 associated with biallelic pathogenic variants in KLHL7, is notable for its few overlapping manifestations. This study presents genotype-phenotype relationships in CS/CISS-like spectrum associated with CRLF1 and KLHL7. Clinical findings of 19 patients from 14 families and four patients from three families were found in association with six different CRLF1 and three different KLHL7 variants, respectively. c.167T>C and c.713delC of the CRLF1 gene and the c.642G>C of the KLHL7 were novel. The c.708_709delCCinsT allele of CRLF1 was identified in 10 families from the Mardin province of Turkey, underlining that an ancestral haplotype has become widespread. CRLF1-associated phenotypes revealed novel manifestations such as prenatal oligohydramnios, benign external hydrocephalus, previously unreported dysmorphic features emerging with advancing age, severe palmoplantar keratoderma and facial erythema, hypopigmented macules and streaks, and recurrent cardiac arrests. KLHL7 variants presented with glabellar nevus flammeus, blepharophimosis, microcephaly, thin corpus callosum, and cleft palate. Abnormalities of sweating, observed in one patient reported herein, is known to be very rare among KLHL7-related phenotypes.

Congenital myasthenic syndromes (CMS) are a heterogeneous group of genetic disorders affecting the safety factor which required for neuromuscular transmission. Here we reported our experience in children with CMS.We retrospectively collected the data of 18 patients with CMS who were examined in our outpatient clinic between January 2021 and January 2022. The diagnosis of CMS was based on the presence of clinical symptoms such as abnormal fatigability and weakness, absence of autoantibodies against acetylcholine receptor and muscle-specific kinase, electromyographic evidence of neuromuscular junction defect, molecular genetic confirmation, and response to treatment.The most common mutations were in the acetylcholine receptor (CHRNE) gene (8/18) and choline acetyltransferase (ChAT) (2/18) gene. Despite targeted gene sequencing and whole exome sequencing (WES) were underwent, we couldn't detect a genetic mutation in three out of patients. The most commonly determined initial finding was eyelid ptosis, followed by fatigable weakness, and respiratory insufficiency. Although the most commonly used drug was pyridostigmine, we have experienced that caution should be exercised as it may worsen some types of CMS.We reported in detail the phenotypic features of very rare gene mutations associated with CMS and our experience in the treatment of this disease. Although CMS are rare genetic disorder, the prognosis can be very promising with appropriate treatment in most CMS subtypes.

Objective: This study aimed to analyze the indications and outcomes of prenatal invasive diagnostic procedures performed in a single tertiary center. Materials and Methods: The invasive procedure indications and karyotype results of 1666 pregnant women who underwent prenatal invasive procedures between March 2016 and November 2018 were retrospectively analyzed. The indications and results of prenatal invasive diagnostic procedures were recorded. Results: Amniocentesis (AS) was performed to 1060 (63.6%) patients, corion villus sampling (CVS) to 299 (17.9%), and cordocentesis (CS) to 307 (18.4%) patients. Among the prenatal invasive procedure indications, the most frequent indication was abnormal ultrasound (US) findings, with a rate of 48.3% (n= 805). A normal karyotype was detected in 85% (n= 1416) of the cases, and chromosomal abnormality was detected in 12.2% (n= 204) of the cases. Abnormal karyotype results were found in 111 (10.5%) of 1060 patients who underwent AS, 87 (29.1%) of 299 patients who underwent CVS, and 52 (16.9%) of 307 patients who underwent CS. Among the numerical chromosomal abnormalities, trisomy 21 was the most common abnormality with a rate of 46% (94/204), while inversions were the most common abnormality of structural chromosomal abnormalities at 8.8% (18/204). Conclusion: The results of the current study show that AS is the most common prenatal diagnostic invasive procedure. We obtained the highest fetal chromosomal anomaly rate in patients who experienced CVS. Abnormal US findings were the most common prenatal invasive diagnostic procedure indication in our study. Choosing the most appropriate invasive procedure is related to the obstetricians' experience, medical history of the patient, the gestational week at admission, maternal prenatal serum screening test results, and abnormal US findings.

Marfan syndrome (MFS) is an autosomal dominant genetic condition that mainly affects connective tissue in many parts of the body. Cardinal manifestations involve the ocular, skeletal, and cardiovascular systems. The diagnosis of MFS relies on the revised Ghent criteria, outlined by international expert opinion to facilitate accurate recognition of this syndrome as well as to improve patient management and counseling. However, it may not always be possible to make a definitive diagnosis according to these criteria in each patient and thus molecular confirmation is necessary in subjects with suspected MFS. This debilitating, if not fatal, disorder is caused by mutations in FBN1, which encodes a major constitutive element of extracellular microfibrils. Here, we present a detailed clinical and molecular analysis of 76 Turkish patients with definitive or suspected MFS diagnosed at our center between 2014 and 2019. We were able to identify a total of 51 different FBN1 variants in our cohort, 31 of which have previously been reported in the relevant scientific literature. The remaining 20 variants have not been documented to date. In one patient, we detected a large deletion including the entire FBN1 gene using the array CGH approach. Currently, there are very few studies on the genotype-phenotype correlation of patients with MFS, and no clear genotype-phenotype maps for MFS have been constructed so far, except for some cases. We believe that our findings will make a rich and peculiar contribution to the elusive genotype-phenotype relationship in MFS, especially in this large and populous ethnic group. WOS:000610028100001 2-s2.0-85099760154 PubMed: 33483584

Objective: Low estriol (uE3) levels in the second-trimester screening for Down syndrome may be the result of fetal demise, congenital abnormalities, or some genetic hormonal disorders of the fetus. Although X-linked ichthyosis, a microdeletion syndrome with mild ichthyosis, which causes steroid sulfatase (STS) deficiency, is the most common genetic cause, second-trimester screening tests calculate the risk for a less common and severe disorder known as the Smith Lemli Opitz syndrome (SLOS). We aimed to investigate the outcomes of pregnancies with low uE3 levels in Down syndrome screening and emphasize the high prevalence of STS deficiency instead of SLOS in such cases. Methods: Fifteen pregnancies with very low uE3 levels and high risk for trisomy and/or SLOS in screening tests were evaluated and tested for STS deficiency and SLOS. Results: Seven of the pregnancies had STS microdeletion syndrome, while additional two cases were supposed to have STS gene mutation according to family and/or postnatal history. Although one fetal death was recorded, no chromosomal abnormality, SLOS, or congenital malformation was recorded in our series. Conclusions: SLOS is a very severe and rare syndrome. The risk estimation for SLOS in screening tests causes stress for pregnant women and healthcare givers. We recommend the addition of risk estimation for STS deficiency when a low uE3 level is detected in the screening test. Amaç: İkinci trimester Down sendromu tarama testlerindeki düşük östriyol (uE3) seviyesi, fetal ölüm, konjenital anormallikler veya fetüsün çeşitli genetik hormonal bozukluklarından kaynaklanabilir. Steroid sülfataz (STS) eksikliğine neden olan ve hafif iktiyozla seyreden bir mikrodelesyon sendromu olan X’e bağlı iktiyoz en yaygın genetik neden olmasına rağmen, ikinci trimester tarama testleri daha az yaygın ve daha şiddetli bir hastalık olan Smith Lemli Opitz Sendromu (SLOS) için risk hesaplamaktadır. Down sendromu taramasında uE3 düzeyi düşük olan gebeliklerin sonuçlarını araştırmayı ve bu gibi durumlarda SLOS yerine STS eksikliğinin yüksek prevalansını vurgulamayı amaçladık. Yöntemler: Tarama testlerinde uE3 seviyeleri çok düşük olan ve trizomi ve/veya SLOS açısından yüksek risk taşıyan on beş gebelik STS eksikliği ve SLOS açısından değerlendirilmiş ve test edilmiştir. Bulgular: Gebeliklerin yedisinde STS mikrodelesyon sendromu bulunurken, ek iki olguda aile ve/veya doğum sonrası öyküye dayanarak STS gen mutasyonu düşünüldü. Bir fetal ölüm tespit edildi. Ek kromozom anomalisi, SLOS veya konjenital malformasyon tespit edilmedi. Sonuçlar: SLOS çok ağır seyreden ve nadir görülen bir sendromdur. Tarama testlerinde SLOS için risk tahmini hamileler ve sağlık çalışanları için strese neden olmaktadır. Anksiyeteyi önlemek için tarama testlerinde düşük bir uE3 seviyesi tespit edildiğinde STS eksikliği için risk tahmininin eklenmesini öneririz.

Aim: The aim of this study is to investigate the role of both major chromosomal abnormalities and thrombophilia parameters in the etiology of patients with recurrent pregnancy loss to provide appropriate genetic counseling to couples who applied to our hospital due to recurrent pregnancy loss.Material and Methods: A total of 306 couples who applied to Başakşehir Çam and Sakura City Hospital Genetic Diseases Diagnosis Center due to recurrent pregnancy loss were included in our study. Chromosome analyzes were performed in all patients and analyzes of thrombophilia parameters were done in 306 women.Results: In our study, chromosomal anomalies other than polymorphisms were detected in 13 (4.25%) of a total of 306 couples. Robertsonian translocation in 4 patients, reciprocal translocation in 3 patients, mosaic chromosome formation in 4 patients, structural chromosomal imbalance (derivative chromosome) in 1 patient and numerical chromosomal anomaly in 1 patient were detected. Chromosome analysis of the remaining 293 pairs were normal. In our study, Factor V Leiden variant was detected in approximately 10% of 306 female cases whose thrombophilia parameters were analyzed, while Factor II G20210A variant was detected in approximately 3.5%. Factor V Leiden variant was found to be homozygous in 3 patients (1%) and heterozygous for Factor V Leiden variant in 27 (8.8%) patients. It was determined that 10 patients (3.3%) were heterozygous for the Factor II G20210A variant. A patient homozygously carrying the factor II G20210A variant was not found in our study.Conclusion: In the light of current information and previous literature studies, we recommend that chromosomal analysis and thrombophilia parameters be evaluated in order to clarify the etiology in couples who are evaluated for recurrent pregnancy loss, since there are treatment possibilities when a cause thought to be related to these parameters is detected these analyzes should be performed especially before assisted reproductive techniques, Amaç: Bu çalışmanın amacı, hastanemize tekrarlayan gebelik kaybı nedeniyle başvuran çiftlere uygun genetik danışmanlık verebilmek için hem majör kromozom anomalilerinin hem de trombofili parametrelerinin etiyolojideki rolünü araştırmaktır.Gereç ve Yöntemler: Çalışmamıza tekrarlayan gebelik kaybı nedeniyle Başakşehir Çam ve Sakura Şehir Hastanesi Genetik Hastalıklar Değerlendirme Merkezi'ne başvuran toplam 306 çift dâhil edildi. Tüm hastalarda kromozom analizleri ve 306 bayanda trombofili parametrelerinin analizleri gerçekleştirildi.Bulgular: Çalışmamızda toplam 306 çiftin 13’ünde (%4,25) polimorfizm dışında kalan kromozomal anomaliler tespit edildi. 4 hastada robertsonian translokasyon, 3 hastada resiprokal traslokasyon, 4 hastada mozaik kromozom kuruluşu, 1 hastada yapısal kromozal dengesizlik (derivatif kromozom) ve 1 hastada sayısal kromozal anomali varlığı tespit edilmiştir. Geriye kalan 293 çiftin kromozom analizi normaldi. Çalışmamızda trombofili parametreleri analiz edilen 306 bayan olgunun yaklaşık %10’unda Faktör V Leiden varyantı saptanırken, Faktör II G20210A varyantı ise yaklaşık %3,5 oranında saptanmıştır. 3 hastada (%1) Faktör V Leiden varyantı homozigot, 27 hastada ise Faktör V Leiden varyantı (%8,8) heterozigot olarak saptanmıştır. 10 hastanın (%3,3) Faktör II G20210A varyantını heterozigot olarak taşıdıkları saptanmıştır. Faktör II G20210A varyantını homozigot olarak taşıtan bir hasta çalışmamızda saptanmamıştır.Sonuç: Mevcut bilgiler ve geçmişteki literatür çalışmaları eşliğinde tekrarlayan gebelik kaybı nedeniyle değerlendirilen çiftlerde etiyolojiyi aydınlatmak için kromozom analizi ve trombofili parametrelerinin değerlendirilmesini ve bu parametrelerde ilişkili olduğu düşünülen bir neden saptandığında tedavi imkanları bulunduğundan dolayı özellikle yardımcı üreme tekniklerinden önce bu analizlerin yapılmasını önermekteyiz.

KIF1A is a molecular motor for membrane-bound cargo important to the development and survival of sensory neurons. KIF1A dysfunction has been associated with several Mendelian disorders with a spectrum of overlapping phenotypes, ranging from spastic paraplegia to intellectual disability. We present a novel pathogenic in-frame deletion in the KIF1A molecular motor domain inherited by two affected siblings from an unaffected mother with apparent germline mosaicism. We identified eight additional cases with heterozygous, pathogenic KIF1A variants ascertained from a local data lake. Our data provide evidence for the expansion of KIF1A-associated phenotypes to include hip subluxation and dystonia as well as phenotypes observed in only a single case: gelastic cataplexy, coxa valga, and double collecting system. We review the literature and suggest that KIF1A dysfunction is better understood as a single neuromuscular disorder with variable involvement of other organ systems than a set of discrete disorders converging at a single locus. National Institutes of Health Revisión por pares

Objective To determine if fetal MR alters the management of pregnancy and family decisions in the isolated corpus callosum agenesis (CCA) cases or not. Methods Fetal MR was carried out in the cases diagnosed with CCA in the Perinatology Unit of our hospital between 2013 and 2019 after they were differentiated as complex and isolated CCA cases. The impact of MR results on the family decisions and their approaches towards termination were assessed. Results A total of 109 out 139 cases were evaluated as isolated CCA. While 93 (85.32%) of them were diagnosed with the complete CCA, 16 (14.68%) cases were diagnosed with the partial CCA. When the period after 2017 during which fetal MR was recommended to all patients was reviewed, it was seen that 7 (23.3%) of 30 cases who underwent fetal MR and 2 (20%) of 10 cases who did not undergo fetal MR terminated their pregnancies. There was no statistical difference between two groups in terms of the decisions of the patients for gestational termination who did and did not undergo fetal MR. Conclusion Fetal MR imaging in the isolated CCA does not change the decisions of the families for the gestational termination. In terms of the termination decision, week of gestation and socio-cultural factors may have more impacts.

Allogeneic hematopoietic stem cell transplantation is the treatment of choice for autosomal recessive osteopetrosis caused by defects in the TCIRG1 gene. Despite recent progress in conditioning, an important number of patients are not eligible for allogeneic stem cell transplantation because of the severity of the disease and significant transplant-related morbidity. We exploited peripheral CD34(+) cells, known to circulate at high frequency in the peripheral blood of TCIRG1-deficient patients, as a novel cell source for autologous transplantation of gene corrected cells. Detailed phenotypical analysis showed that circulating CD34(+). cells have a cellular composition that resembles bone marrow (BM), supporting their use in gene therapy protocols. Transcriptomic profile revealed enrichment in genes expressed by hematopoietic stem and progenitor cells (HSPC). To overcome the limit of BM harvest/HSPC mobilization and serial blood drawings in TCIRG1 patients, we applied UM171-based ex vivo expansion of HSPC coupled with lentiviral gene transfer. Circulating CD34(+). cells from TCIRG1-defective patients were transduced with a clinically-optimized lentiviral vector expressing TCIRG1 under the control of phosphoglycerate promoter and expanded ex vivo. Expanded cells maintained long-term engraftment capacity and multi-lineage repopulating potential when transplanted in vivo both in primary and secondary NOD scid gamma common chain (NSG) recipients. Moreover, when CD34(+) cells were differentiated in vitro, genetically corrected osteoclasts resorbed the bone efficiently. Overall, we provide evidence that expansion of circulating HSPC coupled to gene therapy can overcome the limit of stem cell harvest in osteopetrotic patients, thus opening the way to future gene-based treatment of skeletal diseases caused by BM fibrosis.

Objective: This study aimed to demonstrate the diagnostic value of microarray testing in autism spectrum disorder, intellectual disability, and multiple congenital anomalies of unknown etiology, as well as to report some potential candidate genes for autism. Methods: Microarray analysis records between January 2016 and December 2017 from two Genetic Diagnostic Centers in Turkey, Kanuni Sultan Suleyman and Adana Numune Training and Research Hospital, were compiled. Detected copy number variations (CNVs) were classified as benign, likely benign, variants of uncertain significance (VUS), likely pathogenic, and pathogenic according to American College of Medical Genetics and Genomics guidelines. The clinical findings of the some patients and the literature data were compared. Results: In 109 (24.5%) of 445 patients, a total of 163 CNVs with reporting criterion feature were detected. Sixty-nine (42%) and 8 (5%) of these were evaluated as pathogenic and likely pathogenic, respectively. Fifteen (9%) CNVs were also evaluated as VUS. Pathogenic or likely pathogenic CNVs were detected in 61 (13.6%) of 445 patients. Conclusions: We found that the probability of elucidating the etiology of microarray method in autism spectrum disorder, intellectual disability, and multiple congenital anomalies is 13.6% with a percentage similar to the literature. We suggest that the MYT1L, PXDN, TPO, and AUTS2 genes are all strong candidate genes for autism spectrum disorders. We detailed the clinical findings of the cases and reported that some CNV regions in the genome may be associated with autism. Amaç: Otizm spektrum bozukluğu, zihinsel yetersizlik ve etiyolojisi bilinmeyen çoklu konjenital anomalilerde mikroarray testinin tanısal değerini göstermek ve otizm için bazı potansiyel aday genleri bildirmektir. Yöntemler: Türkiye’deki iki Genetik Tanı Merkezi Kanuni Sultan Süleyman ve Adana Numune Eğitim ve Araştırma Hastanesi’nin Ocak 2016 ile Aralık 2017 tarihleri arasında mikroarray analiz kayıtları derlendi. Tespit edilen kopya sayısı değişimleri (CNV), Amerikan Tıbbi Genetik ve Genomik Koleji kriterlerine göre iyi huylu, olası iyi huylu, klinik önemi belirsiz, olası patojenik ve patojenik olarak sınıflandırıldı. Bazı hastaların klinik bulguları ile literatür verileri karşılaştırıldı. Bulgular: Dört yüz kırk beş hastanın 109’unda (%24,5) raporlama kriteri özelliğine sahip toplam 163 CNV tespit edildi. Bunların 69’u (%42) ve 8’i (%5) sırasıyla patojenik ve olası patojenik olarak değerlendirildi. On beş (%9) CNV de klinik önemi belirsiz varyant olarak değerlendirildi. Dört yüz kırk beş hastanın 61’inde (%13,6) patojenik veya olası patojenik CNV tespit edildi. Sonuçlar: Otizm spektrum bozukluğu, zihinsel yetersizlik ve çoklu doğumsal anomalilerde mikroarray yönteminin etiyolojisini aydınlatma olasılığının literatüre benzer bir yüzdeyle %13,6 olduğunu gösterdik. MYT1L, PXDN, TPO ve AUTS2 genlerinin bir kez daha otizm spektrum bozuklukları için güçlü bir aday gen olduğunu öneriyoruz. Olguların klinik bulgularını detaylandırarak genomda otizm ile ilişkili olabilecek bazı CNV bölgelerini bildirdik.

Contains fulltext : 252015.pdf (Publisher’s version ) (Open Access) Robinow syndrome is characterized by a triad of craniofacial dysmorphisms, disproportionate-limb short stature, and genital hypoplasia. A significant degree of phenotypic variability seems to correlate with different genes/loci. Disturbances of the noncanonical WNT-pathway have been identified as the main cause of the syndrome. Biallelic variants in ROR2 cause an autosomal recessive form of the syndrome with distinctive skeletal findings. Twenty-two patients with a clinical diagnosis of autosomal recessive Robinow syndrome were screened for variants in ROR2 using multiple molecular approaches. We identified 25 putatively pathogenic ROR2 variants, 16 novel, including single nucleotide variants and exonic deletions. Detailed phenotypic analyses revealed that all subjects presented with a prominent forehead, hypertelorism, short nose, abnormality of the nasal tip, brachydactyly, mesomelic limb shortening, short stature, and genital hypoplasia in male patients. A total of 19 clinical features were present in more than 75% of the subjects, thus pointing to an overall uniformity of the phenotype. Disease-causing variants in ROR2, contribute to a clinically recognizable autosomal recessive trait phenotype with multiple skeletal defects. A comprehensive quantitative clinical evaluation of this cohort delineated the phenotypic spectrum of ROR2-related Robinow syndrome. The identification of exonic deletion variant alleles further supports the contention of a loss-of-function mechanism in the etiology of the syndrome.

Purpose A number of mechanisms have been proposed for the effect of chromosomal translocations on spermatogenesis and sperm maturation. However, there are still numerous ambiguous issues regarding these two processes. The aim of this study is to evaluate the effect of chromosome break areas on sperm count in the light of the literature. Material and Methods The study was conducted on the data of 16 male patients with reciprocal or Robertsonian translocation among 152 patients who were admitted to Adana Numune Training and Research Hospital and Kanuni Sultan Süleyman Training and Research Hospital Genetic Diagnosis Centers between 2013 and 2016 due to azoospermia and oligospermia. Results 11 of these patients had reciprocal and five patients had Robertsonian translocations. All the patients with Robertsonian translocations were detected with azoospermia. Of the patients with reciprocal translocation, five of them were azoospermic and six of them were severe oligospermic. Conclusion A total of 21 chromosomal breakpoints were identified in the 11 patients with reciprocal translocations. These chromosomal breakpoints may contribute to the clarification of ambiguous issues related to spermatogenesis and sperm maturation. The results also showed the importance of genetic counselling in patients with translocations.

© 2022 Elsevier B.V.Objective: Joubert syndrome is a neurodevelopmental disorder with a distinctive hindbrain malformation called molar tooth sign, causing motor and cognitive impairments. More than 40 genes have been associated with Joubert syndrome. We aim to describe a group of Joubert syndrome patients clinically and genetically emphasizing organ involvement. Methods: We retrospectively collected clinical information and molecular diagnosis data of 22 patients with Joubert syndrome from multiple facilities. Clinical exome or whole-exome sequencing were performed to identify causal variations in genes. Results: The most common variants were in the CPLANE1, CEP290, and TMEM67 genes, and other causative genes were AHI1, ARMC9, CEP41, CSPP1, HYLS1, KATNIP, KIAA0586, KIF7, RPGRIP1L, including some previously unreported variants in these genes. Multi-systemic organ involvement was observed in nine (40%) patients, with the eye being the most common, including Leber\"s congenital amaurosis, ptosis, and optic nerve coloboma. Portal hypertension and esophageal varices as liver and polycystic kidney disease and nephronophthisis as kidney involvement was encountered in our patients. The HYLS1 gene, which commonly causes hydrolethalus syndrome 1, was also associated with Joubert syndrome in one of our patients. A mild phenotype with hypophyseal hormone deficiencies without the classical molar tooth sign was observed with compound heterozygous and likely pathogenic variants not reported before in the KATNIP gene. Conclusion: Some rare variants that display prominent genetic heterogeneity with variable severity are first reported in our patients. In our study of 22 Joubert syndrome patients, CPLANE1 is the most affected gene, and Joubert syndrome as a ciliopathy is possible without a classical molar tooth sign, like in the KATNIP gene-affected patients.

MaterialLinked-read whole genome sequencing (WGS) presents a new opportunity for cost-efficient singleton sequencing in place of traditional trio-based designs while generating informative-phased variants, effective for recessive disorders when parental DNA is unavailable.MethodsWe have applied linked-read WGS to identify novel causes of Meier-Gorlin syndrome (MGORS), a condition recognised by short stature, microtia and patella hypo/aplasia. There are eight genes associated with MGORS to date, all encoding essential components involved in establishing and initiating DNA replication.ResultsOur successful phasing of linked-read data led to the identification of biallelic rare variants in four individuals (24% of our cohort) in DONSON, a recently established DNA replication fork surveillance factor. The variants include five novel missense and one deep intronic variant. All were demonstrated to be deleterious to function; the missense variants all disrupted the nuclear localisation of DONSON, while the intronic variant created a novel splice site that generated an out-of-frame transcript with no residual canonical transcript produced.ConclusionVariants in DONSON have previously been associated with extreme microcephaly, short stature and limb anomalies and perinatal lethal microcephaly-micromelia syndrome. Our novel genetic findings extend the complicated spectrum of phenotypes associated with DONSON variants and promote novel hypotheses for the role of DONSON in DNA replication. While our findings reiterate that MGORS is a disorder of DNA replication, the pathophysiology is obviously complex. This successful identification of a novel disease gene for MGORS highlights the utility of linked-read WGS as a successful technology to be considered in the genetic studies of recessive conditions.

Background: Hereditary cholestasis is a heterogeneous group of liver diseases that mostly show autosomal recessive inheritance. The phenotype of cholestasis is highly variable. Molecular genetic testing offers a useful approach to differentiate different types of cholestasis because some symptoms and findings overlap. Biallelic variants in USP53 have recently been reported in cholestasis phenotype. In this study we aim to characterize clinical findings and biological insights on a novel USP53 splice variant causing cholestasis phenotype and review of the literature. Methods and Results: We reported a novel splice variant (NM_019050.2:c.238-1G>C) in the USP53 gene via whole exome sequencing in a patient with cholestasis phenotype. This variant was confirmed by sanger sequencing and as a result of family segregation analysis; it was found to be a heterozygous state in the parents and the other healthy elder brother of our patient. According to in-silico analyses; the change in the splice region resulted in an increase in the length of exon 1, whereas the stop codon after the additional 3 amino acids (VTF) caused the protein to terminate prematurely. Thus, the mature USP53 protein, consisting of 1.073 amino acids, has been reduced to a small protein of 82 amino acids.Conclusions: We propose a model for the tertiary structure of USP53 for the first time, together with all these data, we support the association of biallelic variants of the USP53 gene with the cholestasis phenotype. We also presented a comparison of previously reported patients with the USP53-associated cholestasis phenotype to contribute to the literature.

Background: Maturity-onset diabetes of the young (MODY), which is the most common cause of monogenic diabetes, has an autosomal dominant pattern of inheritance and exhibits marked clinical and genetic heterogeneity. The aim of the current study was to investigate molecular defects in patients with clinically suspected MODY using a next-generation sequencing (NGS)-based targeted gene panel. Candidate patients with clinical suspicion of MODY and their parents were included in the study. Molecular genetic analyses were performed on genomic DNA by using NGS. A panel of thirteen MODY-related genes involving ABCC8, BLK, CEL, GCK, HNF1A, HNF1B, HNF4A, INS, KCNJ11, KLF11, NEUROD1, PAX4, PDX1 was designed and subsequently implemented to screen 44 patients for genetic variants. Ten different pathogenic or likely pathogenic variants were identified in MODY-suspected patients, with a diagnostic rate of 22.7%. Eight variants of uncertain significance were also detected. Four novel pathogenic or likely pathogenic variants were detected in the genes GCK (c.1301G>T [p.Cys434Phe]), HNF1A (c.505_506delAA [p.Lys169AlafsTer18]), ABCC8 (c.3584C>T [p.Thr1195Ile]), and CEL (c.679-1G>A). Intriguingly, we were able to detect variants associated with rare forms of MODY in our study population. Our results suggest that in heterogenous diseases such as MODY, NGS analysis enables accurate identification of underlying molecular defects in a timely and cost-effective manner. Although MODY accounts for 1–2% of all diabetic cases, molecular genetic diagnosis of MODY is necessary for optimal long-term treatment and prognosis as well as for effective genetic counseling.

Leukocyte adhesion deficiency is an autosomal recessive primary immunodeficiency that has been divided into three types: LAD1 (beta-2 integrin (CD18) family deficiency/defect), LAD2 (absence of fucosylated carbonhydrate ligands for selectins) and LAD3 (defective activation of all beta integrins). However, recently LAD4 has been described in cystic fibrosis patients, with a defect in integrin activation reported in monocytes. LAD-I is the most common type and prevalence of 1 in 1,000,000 live births. Clinical features of LAD patients are recurrent bacterial and fungal infections, omphalitis with delayed umbilical stump separation, significant leukocytosis especially neutrophilia during infection periods, impaired pus formation, and delayed traumatic or surgical wound healing. Flow cytometry is considered a useful tool for rapid diagnosis of the disease. The study of CD18 and CD11 (a, b, c) expression patterns in peripheral blood leukocytes helps to distinguish different phenotypes of LAD-I. In general, patients with >= 2% CD18 expression tend to have a less severe infection and often survive until adulthood, whereas < 2% CD18 expression often results in death in infancy. In this case report, three siblings, 10, 15, and 17 years old, diagnosed with leukocyte adhesion defect type 1 in adolescence age group, are presented.

3M syndrome is characterized by severe pre- and post-natal growth restriction, typical face, slender tubular bones, tall vertebral bodies, prominent heels and normal intelligence. It is caused by biallelic variants of CUL7, OBSL1 and, more rarely, CCDC8. The aim of this study is to evaluate facial and skeletal findings in 3M patients from neonatal period to adulthood. A total of 19 patients with a median age of diagnosis of 9.2 months were included in this study and were followed for two to 20 years. CUL7 and OBSL1 variants were found in 57.9% and 42.1% of patients, respectively, five of which are novel. Most of patients had triangular face, frontal bossing, short fleshy nose, full fleshy lower lip, transverse groove of rib cage, hyperlordosis and prominent heels. Three new early-diagnostic signs were observed in infants; two were infraorbital swelling of the lower lid and facial infantile hemangioma, both of which became less pronounced with aging. The third was the central tubercle of the upper lip that became more prominent with in time. While slender long bones did not change with aging, the tall vertebral bodies became more prominent radiologically. The mean birth length in patients was −4.3 SDS. Eight patients reached a mean final height of −4.9 SDS. Despite described growth hormone (GH) insensitivity in 3M syndrome, 12 patients either with GH deficiency or with normal GH levels were treated with GH; seven patients responded with an increase in height SDS. This study not only provided early diagnostic signs of the syndrome, but also presented important follow-up findings.

Summary Latent transforming growth factor β (TGFβ)-binding proteins (LTBPs) are microfibril-associated proteins essential for anchoring TGFβ in the extracellular matrix (ECM) as well as for correct assembly of ECM components. Variants in LTBP2, LTBP3, and LTBP4 have been identified in several autosomal recessive Mendelian disorders with skeletal abnormalities with or without impaired development of elastin-rich tissues. Thus far, the human phenotype associated with LTBP1 deficiency has remained enigmatic. In this study, we report homozygous premature truncating LTBP1 variants in eight affected individuals from four unrelated consanguineous families. Affected individuals present with connective tissue features (cutis laxa and inguinal hernia), craniofacial dysmorphology, variable heart defects, and prominent skeletal features (craniosynostosis, short stature, brachydactyly, and syndactyly). In vitro studies on proband-derived dermal fibroblasts indicate distinct molecular mechanisms depending on the position of the variant in LTBP1. C-terminal variants lead to an altered LTBP1 loosely anchored in the microfibrillar network and cause increased ECM deposition in cultured fibroblasts associated with excessive TGFβ growth factor activation and signaling. In contrast, N-terminal truncation results in a loss of LTBP1 that does not alter TGFβ levels or ECM assembly. In vivo validation with two independent zebrafish lines carrying mutations in ltbp1 induce abnormal collagen fibrillogenesis in skin and intervertebral ligaments and ectopic bone formation on the vertebrae. In addition, one of the mutant zebrafish lines shows voluminous and hypo-mineralized vertebrae. Overall, our findings in humans and zebrafish show that LTBP1 function is crucial for skin and bone ECM assembly and homeostasis.

Objective To characterize the molecular and clinical phenotypic basis of developmental and epileptic encephalopathies caused by rare biallelic variants in CACNA2D2. Methods Two affected individuals from a family with clinical features of early onset epileptic encephalopathy were recruited for exome sequencing at the Centers for Mendelian Genomics to identify their molecular diagnosis. GeneMatcher facilitated identification of a second family with a shared candidate disease gene identified through clinical gene panel‐based testing. Results Rare biallelic CACNA2D2 variants have been previously reported in three families with developmental and epileptic encephalopathy, and one family with congenital ataxia. We identified three individuals in two unrelated families with novel homozygous rare variants in CACNA2D2 with clinical features of developmental and epileptic encephalopathy and cerebellar atrophy. Family 1 includes two affected siblings with a likely damaging homozygous rare missense variant c.1778G>C; p.(Arg593Pro) in CACNA2D2. Family 2 includes a proband with a homozygous rare nonsense variant c.485_486del; p.(Tyr162Ter) in CACNA2D2. We compared clinical and molecular findings from all nine individuals reported to date and note that cerebellar atrophy is shared among all. Interpretation Our study supports the candidacy of CACNA2D2 as a disease gene associated with a phenotypic spectrum of neurological disease that include features of developmental and epileptic encephalopathy, ataxia, and cerebellar atrophy. Age at presentation may affect apparent penetrance of neurogenetic trait manifestations and of a particular clinical neurological endophenotype, for example, seizures or ataxia.

Context: Primary ovarian insufficiency (POI) encompasses a spectrum of premature menopause, including both primary and secondary amenorrhea. For 75% to 90% of individuals with hyper-gonadotropic hypogonadism presenting as POI, the molecular etiology is unknown. Common etiologies include chromosomal abnormalities, environmental factors, and congenital disorders affecting ovarian development and function, as well as syndromic and nonsyndromic single gene disorders suggesting POI represents a complex trait. Objective: To characterize the contribution of known disease genes to POI and identify molecular etiologies and biological underpinnings of POI. Design, Setting, and Participants: We applied exome sequencing (ES) and family-based genomics to 42 affected female individuals from 36 unrelated Turkish families, including 31 with reported parental consanguinity. Results: This analysis identified likely damaging, potentially contributing variants and molecular diagnoses in 16 families (44%), including 11 families with likely damaging variants in known genes and five families with predicted deleterious variants in disease genes (IGSF10, MND1, MRPS22, and SOHLH1) not previously associated with POI. Of the 16 families, 2 (13%) had evidence for potentially pathogenic variants at more than one locus. Absence of heterozygosity consistent with identity-by-descent mediated recessive disease burden contributes to molecular diagnosis in 15 of 16 (94%) families. GeneMatcher allowed identification of additional families from diverse genetic backgrounds. Conclusions: ES analysis of a POI cohort further characterized locus heterogeneity, reaffirmed the association of genes integral to meiotic recombination, demonstrated the likely contribution of genes involved in hypothalamic development, and documented multilocus pathogenic variation suggesting the potential for oligogenic inheritance contributing to the development of POI. National Human Genome Research Institute (NHGRI)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Human Genome Research Institute (NHGRI); National Heart Lung and Blood Institute (NHBLI)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Heart Lung & Blood Institute (NHLBI) [UM1 HG006542]; National Institute of Neurologic Disorders and Stroke (NINDS)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Neurological Disorders & Stroke (NINDS) [R35NS105078]; NHGRIUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Human Genome Research Institute (NHGRI) [K08 HG008986, U54HG003273]; Howard Hughes Medical Research Fellows Program; Baylor College of Medicine Medical Scientist Training Program; Clinical Research Training Scholarship in Neuromuscular Disease; American Academy of Neurology (AAN); American Brain Foundation (ABF); Netherlands Organization for Scientific Research (ZonMW Veni)Netherlands Organization for Scientific Research (NWO) [91617021]; NARSAD Young Investigator Grant from the Brain & Behavior Research FoundationNARSAD; Muscle Study Group (MSG) This study was supported in part by the National Human Genome Research Institute (NHGRI) and National Heart Lung and Blood Institute (NHBLI) to the Baylor-Hopkins Center for Mendelian Genomics (BHCMG; UM1 HG006542 to J.R.L.); NHGRI grant to Baylor College of Medicine Human Genome Sequencing Center (U54HG003273 to R.A.G.), and National Institute of Neurologic Disorders and Stroke (NINDS; R35NS105078 to J.R.L.). J.E.P. was supported by NHGRI K08 HG008986. A.J. was supported in part by the Howard Hughes Medical Research Fellows Program and the Baylor College of Medicine Medical Scientist Training Program. D. P. is supported by Clinical Research Training Scholarship in Neuromuscular Disease partnered by the American Academy of Neurology (AAN), American Brain Foundation (ABF), and Muscle Study Group (MSG). T.S.B. was supported by the Netherlands Organization for Scientific Research (ZonMW Veni, Grant 91617021) and by an NARSAD Young Investigator Grant from the Brain & Behavior Research Foundation. WOS:000482558500001 31042289 Q1

NTNG2 encodes netrin-G2, a membrane-anchored protein implicated in the molecular organization of neuronal circuitry and synaptic organization and diversification in vertebrates. In this study, through a combination of exome sequencing and autozygosity mapping, we have identified 16 individuals (from seven unrelated families) with ultra-rare homozygous missense variants in NTNG2; these individuals present with shared features of a neurodevelopmental disorder consisting of global developmental delay, severe to profound intellectual disability, muscle weakness and abnormal tone, autistic features, behavioral abnormalities, and variable dysmorphisms. The variants disrupt highly conserved residues across the protein. Functional experiments, including in silico analysis of the protein structure, in vitro assessment of cell surface expression, and in vitro knockdown, revealed potential mechanisms of pathogenicity of the variants, including loss of protein function and decreased neurite outgrowth. Our data indicate that appropriate expression of NTNG2 plays an important role in neurotypical development.

L-2-hydroxyglutaric aciduria (L2HGA) is an autosomal recessive disorder that is caused by deficiency of 2-hydroxyglutarate dehydrogenase. Pathophysiology of brain damage is poorly understood. In recent years, it was proposed that oxidative stress was elevated and led to brain injury. Aim of this study is to evaluate thiol/disulphide homeostasis as an indicator of oxidative stress in L2HGA patients who have been receiving antioxidant treatment. Sixteen L2HGA patients and 16 healthy individuals were included in the study. All the L2HGA patients were regularly followed up and presented neurological dysfunction at different grades. Fourteen patients had been receiving antioxidant treatment. Serum native thiol (-SH), total thiol (-SH + -S-S-) and disulphide (-S-S) levels were measured. Disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated from these values. No significant difference was observed in -SH, -SH + -S-S-, -S-S levels between two groups. In addition to that, no increase of disulphide/native thiol and disulphide/total thiol ratios was detected. Thiol/disulphide homeostasis parameters were also compared between patients who had been receiving and not receiving antioxidant therapy; and between different types of antioxidant therapy and the results did not point to any significant difference. This is the first study that evaluates dynamic thiol/disulphide homeostasis as an indicator of oxidative stress in L2HGA and it has one of the largest sample sizes among previous studies. In our study we suggest that antioxidant therapy should be effective in preventing oxidative stress in L2HGA patients, which has been reported in previous studies and should be a part of standard therapy.

Dysfunction of motile monocilia, altering the leftward flow at the embryonic node essential for determination of left-right body asymmetry, is a major cause of laterality defects. Laterality defects are also often associated with reduced mucociliary clearance caused by defective multiple motile cilia of the airway and are responsible for destructive airway disease. Outer dynein arms (ODAs) are essential for ciliary beat generation, and human respiratory cilia contain different ODA heavy chains (HCs): the panaxonemally distributed gamma-HC DNAH5, proximally located beta-HC DNAH11 (defining ODA type 1), and the distally localized beta-HC DNAH9 (defining ODA type 2). Here we report loss-of-function mutations in DNAH9 in five independent families causing situs abnormalities associated with subtle respiratory ciliary dysfunction. Consistent with the observed subtle respiratory phenotype, high-speed video microscopy demonstrates distally impaired ciliary bending in DNAH9 mutant respiratory cilia. DNAH9-deficient cilia also lack other ODA components such as DNAH5, DNAI1, and DNAI2 from the distal axonemal compartment, demonstrating an essential role of DNAH9 for distal axonemal assembly of ODAs type 2. Yeast two-hybrid and co-immunoprecipitation analyses indicate interaction of DNAH9 with the ODA components DNAH5 and DNAI2 as well as the ODA-docking complex component CCDC114. We further show that during ciliogenesis of respiratory cilia, first proximally located DNAH11 and then distally located DNAH9 is assembled in the axoneme. We propose that the beta-HC paralogs DNAH9 and DNAH11 achieved specific functional roles for the distinct axonemal compartments during evolution with human DNAH9 function matching that of ancient beta-HCs such as that of the unicellular Chlamydomonas reinhardtii.