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Enlarged vestibular aqueduct (EVA) is a frequently occurring inner ear malformation that associates with sensorineural hearing loss (SNHL), with SLC26A4 being the responsible gene. Based on multiplex PCR enrichment and sequencing of the exonic and flanking regions of the SLC26A4 gene, we developed a panel specifically for EVA and found that up to 95% of EVA patients in our Chinese cohorts carried biallelic SLC26A4 pathogenic variants (M2). In this study, we tried to investigate the genetic etiology of 13 previously undiagnosed EVA patients with monoallelic (M1) or none (M0) SLC26A4 variant using a stepwise approach, including copy number variation (CNV) analysis of multiplex PCR enrichment and next‐generation sequencing data, single‐molecule real‐time (SMRT) sequencing of the whole SLC26A4 gene, whole exome sequencing (WES), and whole genome sequencing (WGS). CNV analysis revealed deletions in Exons 1–3, Exons 5–6, and Exons 9–10 of the SLC26A4 gene in seven patients, and SMRT sequencing identified the same heterozygous deep intronic variant (NM_000441.2:c.304+941C>T) in two patients, resulting in a final diagnosis in 9/13 patients. Notably, the variants of Exons 9–10 deletion and c.304+941C>T have not been reported previously. We further showed that the variant c.304+941C>T led to the exonization of partial AluSz6 element (126 bp) where the variant is located through sequencing of the mRNA extracted from the blood of a heterozygous variant carrier. In conclusion, our stepwise approach improved the diagnosis rate of EVA, expanded the mutational spectrum of the SLC26A4 gene, and highlighted the contribution of exonic deletions and deep intronic variants to EVA. [ABSTRACT FROM AUTHOR]

Background: While cochlear implantation (CI) and electric acoustic stimulation (EAS) have a positive outcome in most cases, their effectiveness varies depending on the etiology of the hearing loss. Among the various etiologies, genetic factors are the leading cause of hearing loss and may impact CI and EAS outcomes. Aims/Objectives: To reveal the genetic background of the hearing loss in CI/EAS patients in each ethnic population, we undertook a multi-center study involving the genetic testing of hearing loss in CI/EAS patients from 10 centers. Material and Methods: Saliva samples and clinical information for the patients and their family members were obtained and next-generation sequencing analysis using a panel carrying 63 deafness genes was then performed. Results: Genetic testing successfully identified the causative gene variants in 54.5% (48/88) of patients with pre-lingual onset hearing loss (onset under 6 years) and in 12% (12/95) of those with late-onset hearing loss (onset at 6 years or more). Conclusions and Significance: We clearly indicated that genetic factors are the most common cause of hearing loss regardless of ethnic background. Saliva-based genetic testing is a useful tool for multi-center studies seeking to clarify the genetic causes of hearing loss in CI or EAS patients between countries separated by distance. [ABSTRACT FROM AUTHOR]

After GJB2, SLC26A4 is the second most common contributor to autosomal recessive nonsyndromic hearing loss (ARNSHL) worldwide. In this study, we used Exome Sequencing (ES) to present a village with 31 individuals affected by hereditary hearing loss (HHL) in southeastern Iran near the border of Pakistan. The village harbored the known pathogenic missense SLC26A4 (NM_000441.2):c.716T>A (p.Val239Asp) mutation, which has a founder effect attributed to Pakistan, Iran's southeastern neighbor. Our findings, in addition to unraveling the molecular cause of non-syndromic hearing loss in these patients and further confirming the common ancestry and migration story between the people of this region and Pakistan, provide further insight into the genetic background of this region and highlight the importance of understanding the mutation spectrum of GJB2 and SLC26A4 in different regions to choose cost-effective strategies for molecular genetic testing. [ABSTRACT FROM AUTHOR]

Objectives: Pendred syndrome, an autosomal recessive disorder, is often associated with pathogenic variants of the SLC26A4 gene that encodes the pendrin protein. Given its autosomal recessive inheritance, tracing the family history and screening siblings become crucial once a diagnosis of Pendred syndrome is confirmed. This case report aims to underscore the variability in inner ear morphology within a family diagnosed with Pendred syndrome, all carrying the same SLC26A4 gene mutation. Methods: A chart review and a review of the literature. Results: We present a family of 4, all of whom possess sensorineural hearing loss due to the same homozygous SLC26A4 variant c.919-2A>G. Intriguingly, clinical manifestations, especially inner ear deformities, displayed variability among family members. Notably, 1 family member exhibited a normal cochleovestibular structure morphology, which was rarely reported in the literature. Conclusions: This report highlights the significance of genetic testing and familial consultation when a proband exhibits typical Pendred syndrome symptoms. It also underscores that the inner ear morphology can exhibit variability among family members, even with the same homozygous SLC26A4 variant. [ABSTRACT FROM AUTHOR]

Objective To determine the prevalence and types of mutations in deafness-related genes in Xianyang, providing a theoretical basis and data support for clinical counselling on deafness prevention and treatment. Methods A total of 27 660 newborns born in our hospital between January 2019 and February 2023 were screened for hearing and deafness-related genes using otoacoustic emission, automated auditory brainstem response, polymerase chain reaction (PCR) for detecting 15 mutation sites of the common deafness genes (GJB2, GJB3, SLC26A4 and MT-RNR1), as well as validation through Sanger sequencing for positive samples. Results Among the 27 660 newborns, 1 183(4.27%) were carriers of deafness gene mutations, including 570 (2.06%) of GJB2 gene mutations, 528 (1.91%) of SLC26A4 gene mutations, and 16 (0.06%) of GJB3 gene mutations, and MT-RNR1 gene mutation found in 50 cases (0.18%). There were also compound heterozygous mutation (15 cases, 0.05%) and homozygous mutation (4 cases, 0.01%). Three cases of hearing loss were detected, including two cases with GJB2 c.235delC homozygous mutation and one case with SLC26A4 c. 919- 2 A>G homozygous mutation. Conclusion The high prevalence rate of sensorineural deafness among the newborns in the area is mainly attribute to GJB2 and SLC26A4 gene mutations. Screening for these genetic defects can provide valuable advice to families affected by hearing loss gene, thereby reducing the incidence of hearing loss. [ABSTRACT FROM AUTHOR]

Inner ear malformations are predominantly attributed to developmental arrest during the embryonic stage of membranous labyrinth development. Due to the inherent difficulty in clinically assessing the status of the membranous labyrinth, these malformations are diagnosed with radiographic imaging, based on the morphological characteristics of the bony labyrinth. While extensive research has elucidated the intricacies of membranous labyrinth development in mouse models, comprehensive investigations into the developmental trajectory of the bony labyrinth, especially about its calcification process, have been notably lacking. One of the most prominent types of inner ear malformations is known as incomplete partition (IP), characterized by nearly normal external cochlear appearance but pronounced irregularities in the morphology of the modiolus and inter-scalar septa. IP type II (IP-II), also known as Mondini dysplasia, is generally accompanied by an enlargement of the vestibular aqueduct and is primarily attributed to mutations in the SLC26A4 gene. In the case of IP-II, the modiolus and inter-scalar septa of the cochlear apex are underdeveloped or missing, resulting in the manifestation of a cystic structure on radiographic imaging. In this overview, we not only explore the normal development of the bony labyrinth in mice but also present our observations on otolith mineralization. Furthermore, we investigated the specifics of bony labyrinth and otolith mineralization in Slc26a4-deficient mice, which served as an animal model for IP-II. We ensured that these findings promise to provide valuable insights for the establishment of therapeutic interventions, optimal timing, targeted sites, and preventive measures when considering the management of this condition. [ABSTRACT FROM AUTHOR]

Solute carrier family 26 member 4 (SLC26A4) is a member of the SLC26A transporter family and is expressed in various tissues, including the airway epithelium, kidney, thyroid, and tumors. It transports various ions, including bicarbonate, chloride, iodine, and oxalate. As a multiple-ion transporter, SLC26A4 is involved in the maintenance of hearing function, renal function, blood pressure, and hormone and pH regulation. In this review, we have summarized the various functions of SLC26A4 in multiple tissues and organs. Moreover, the relationships between SLC26A4 and other channels, such as cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, and sodium chloride cotransporter, are highlighted. Although the modulation of SLC26A4 is critical for recovery from malfunctions of various organs, development of specific inducers or agonists of SLC26A4 remains challenging. This review contributes to providing a better understanding of the role of SLC26A4 and development of therapeutic approaches for the SLC26A4-associated hearing loss and SLC26A4-related dysfunction of various organs. [ABSTRACT FROM AUTHOR]

Introduction: Myocardial ischemia-reperfusion (IR) injury has received widespread attention due to its damaging effects. Electroacupuncture (EA) pretreatment has preventive effects on myocardial IR injury. SLC26A4 is a Na+ independent anion reverse transporter and has not been reported in myocardial IR injury. Objectives: To find potential genes that may be regulated by EA and explore the role of this gene in myocardial IR injury. Methods: RNA sequencing and bioinformatics analysis were performed to obtain the differentially expressed genes in the myocardial tissue of IR rats with EA pretreatment. Myocardial infarction size was detected by TTC staining. Serum CK, creatinine kinase-myocardial band, Cardiac troponin I, and lactate dehydrogenase levels were determined by ELISA. The effect of SLC26A4 on cardiomyocyte apoptosis was explored by TUNEL staining and western blotting. The effects of SLC26A4 on inflammation were determined by HE staining, ELISA, and real-time PCR. The effect of SLC26A4 on the NF-κB pathway was determined by western blotting. Results: SLC26A4 was up-regulated in IR rats but downregulated in IR rats with EA pretreatment. Compared with IR rats, those with SLC26A4 knockdown exhibited improved cardiac function according to decreased myocardial infarction size, reduced serum LDH/CK/CKMB/ cTnI levels, and elevated left ventricular ejection fraction and fractional shortening. SLC26A4 silencing inhibited myocardial inflammation, cell apoptosis, phosphorylation, and nuclear translocation of NF-κB p65. Conclusion: SLC26A4 exhibited promoting effects on myocardial IR injury, while the SLC26A4 knockdown had an inhibitory effect on the NF-κB pathway. These results further unveil the role of SLC26A4 in IR injury. [ABSTRACT FROM AUTHOR]

Pendrin and prestin are evolutionary-conserved membrane proteins that are essential for normal hearing. Dysfunction of these proteins results in hearing loss in humans, and numerous deafness-associated pendrin and prestin variants have been identified in patients. However, the pathogenic impacts of many of these variants are ambiguous. Here, we report results from our ongoing efforts to experimentally characterize pendrin and prestin variants using in vitro functional assays. With previously established fluorometric anion transport assays, we determined that many of the pendrin variants identified on transmembrane (TM) 10, which contains the essential anion binding site, and on the neighboring TM9 within the core domain resulted in impaired anion transport activity. We also determined the range of functional impairment in three deafness-associated prestin variants by measuring nonlinear capacitance (NLC), a proxy for motor function. Using the results from our functional analyses, we also evaluated the performance of AlphaMissense (AM), a computational tool for predicting the pathogenicity of missense variants. AM prediction scores correlated well with our experimental results; however, some variants were misclassified, underscoring the necessity of experimentally assessing the effects of variants. Together, our experimental efforts provide invaluable information regarding the pathogenicity of deafness-associated pendrin and prestin variants. [ABSTRACT FROM AUTHOR]

Abstract Background Gene variants are responsible for more than half of hearing loss, particularly in nonsyndromic hearing loss (NSHL). The most common pathogenic variant in SLC26A4 gene found in East Asian populations is c.919-2A > G followed by c.2168A > G (p.H723R). This study was to evaluate their variant frequencies in patients with NSHL from special education schools in nine different areas of Southwest China’s Yunnan. Methods We performed molecular characterization by PCR-products directly Sanger sequencing of the SLC26A4 c.919-2AG and c.2168 A > G variants in 1167 patients with NSHL including 533 Han Chinese and 634 ethnic minorities. Results The SLC26A4 c.919-2A > G variant was discovered in 8 patients with a homozygous state (0.69%) and twenty-five heterozygous (2.14%) in 1167 patients with NSHL. The total carrier rate of the c.919-2A > G variant was found in Han Chinese patients with 4.50% and ethnic minority patients with 1.42%. A significant difference existed between the two groups (P G allele variant frequency was ranged from 3.93% in Kunming to zero in Lincang and Nvjiang areas of Yunnan. We further detected the SLC26A4 c.2168 A > G variant in this cohort with one homozygotes (0.09%) and seven heterozygotes (0.60%), which was detected in Baoshan, Honghe, Licang and Pu`er areas. Between Han Chinese group (0.94%) and ethnic minority group (0.47%), there was no statistical significance (P > 0.05). Three Han Chinese patients (0.26%) carried compound heterozygosity for c.919-2A > G and c.2168 A > G. Conclusion These data suggest that the variants in both SLC26A4 c.919-2A > G and c.2168 A > G were relatively less frequencies in this cohort compared to the average levels in most regions of China, as well as significantly lower than that in Han-Chinese patients. These results broadened Chinese population genetic information resources and provided more detailed information for regional genetic counselling for Yunnan.

Background: Gene variants are responsible for more than half of hearing loss, particularly in nonsyndromic hearing loss (NSHL). The most common pathogenic variant in SLC26A4 gene found in East Asian populations is c.919-2A > G followed by c.2168A > G (p.H723R). This study was to evaluate their variant frequencies in patients with NSHL from special education schools in nine different areas of Southwest China's Yunnan. Methods: We performed molecular characterization by PCR-products directly Sanger sequencing of the SLC26A4 c.919-2AG and c.2168 A > G variants in 1167 patients with NSHL including 533 Han Chinese and 634 ethnic minorities. Results: The SLC26A4 c.919-2A > G variant was discovered in 8 patients with a homozygous state (0.69%) and twenty-five heterozygous (2.14%) in 1167 patients with NSHL. The total carrier rate of the c.919-2A > G variant was found in Han Chinese patients with 4.50% and ethnic minority patients with 1.42%. A significant difference existed between the two groups (P < 0.05). The c.919-2A > G allele variant frequency was ranged from 3.93% in Kunming to zero in Lincang and Nvjiang areas of Yunnan. We further detected the SLC26A4 c.2168 A > G variant in this cohort with one homozygotes (0.09%) and seven heterozygotes (0.60%), which was detected in Baoshan, Honghe, Licang and Pu'er areas. Between Han Chinese group (0.94%) and ethnic minority group (0.47%), there was no statistical significance (P > 0.05). Three Han Chinese patients (0.26%) carried compound heterozygosity for c.919-2A > G and c.2168 A > G. Conclusion: These data suggest that the variants in both SLC26A4 c.919-2A > G and c.2168 A > G were relatively less frequencies in this cohort compared to the average levels in most regions of China, as well as significantly lower than that in Han-Chinese patients. These results broadened Chinese population genetic information resources and provided more detailed information for regional genetic counselling for Yunnan. [ABSTRACT FROM AUTHOR]

Objective: We aimed to evaluate the genotype–phenotype relationship in two Chinese family members with enlarged vestibular aqueduct (EVA). Methods: We collected blood samples and clinical data from each pedigree family member. Genomic DNA was isolated from peripheral leukocytes using standard methods. Targeted next‐generation sequencing and Sanger sequencing were performed to find the pathogenic mutation in this family. Minigene assays were used to verify whether the novel intronic mutation SLC26A4c.765+4A>G influenced mRNA splicing. Results: Hearing loss in the patients with EVA was diagnosed using auditory tests and imaging examinations. Two pathogenic mutations, c.765+4A>G and c.919‐2A>G were detected in SLC26A4. In vitro minigene analysis confirmed that c.765+4A>G variant could cause aberrant splicing, resulting in skipping over exon 6. Conclusions: The SLC26A4c.765+4A>G mutation is the causative variant in the Chinese family with EVA. Particular attention should be paid to intronic variants. [ABSTRACT FROM AUTHOR]

Background: Preconception or prenatal carrier screening plays an important role in reproductive decision-making, but current research on hereditary deafness is limited. This study aimed to investigate the carrier frequencies of common deafness genes in the Chinese population who underwent carrier screening and to follow up on pregnancy outcomes in high-chance couples. Methods: Individual females or couples in preconception or early pregnancy were recruited from two hospitals in China. Carrier screening for common deafness genes in the Chinese population, including the GJB2 and SLC26A4 genes, was performed using next-generation sequencing technology. Genetic counseling was provided to subjects before and after testing. Results: Of the 9,993 subjects screened, the carrier rate was 2.86% for the GJB2 gene and 2.63% for the SLC26A4 gene. The variant with the highest carrier frequency in GJB2 was c.235delC (1.89%), and c.919-2A>G (1.08%) in SLC26A4. Of the six high-chance couples, four made alternative reproductive decisions (three with prenatal diagnosis and one with preimplantation genetic testing), with consequent termination of the birth of two affected fetuses. Conclusion: These findings confirmed the clinical utility of preconception or prenatal carrier screening for hereditary deafness. [ABSTRACT FROM AUTHOR]

Abstract Background The primary pathological alterations of Pendred syndrome are endolymphatic pH acidification and luminal enlargement of the inner ear. However, the molecular contributions of specific cell types remain poorly characterized. Therefore, we aimed to identify pH regulators in pendrin-expressing cells that may contribute to the homeostasis of endolymph pH and define the cellular pathogenic mechanisms that contribute to the dysregulation of cochlear endolymph pH in Slc26a4 −/− mice. Methods We used single-cell RNA sequencing to identify both Slc26a4-expressing cells and Kcnj10-expressing cells in wild-type (WT, Slc26a4 +/+) and Slc26a4 −/− mice. Bioinformatic analysis of expression data confirmed marker genes defining the different cell types of the stria vascularis. In addition, specific findings were confirmed at the protein level by immunofluorescence. Results We found that spindle cells, which express pendrin, contain extrinsic cellular components, a factor that enables cell-to-cell communication. In addition, the gene expression profile informed the pH of the spindle cells. Compared to WT, the transcriptional profiles in Slc26a4 −/− mice showed downregulation of extracellular exosome-related genes in spindle cells. Immunofluorescence studies in spindle cells of Slc26a4 −/− mice validated the increased expression of the exosome-related protein, annexin A1, and the clathrin-mediated endocytosis-related protein, adaptor protein 2. Conclusion Overall, cell isolation of stria vascularis from WT and Slc26a4 −/− samples combined with cell type-specific transcriptomic analyses revealed pH-dependent alternations in spindle cells and intermediate cells, inspiring further studies into the dysfunctional role of stria vascularis cells in SLC26A4-related hearing loss.

Abstract Objective We aimed to evaluate the genotype–phenotype relationship in two Chinese family members with enlarged vestibular aqueduct (EVA). Methods We collected blood samples and clinical data from each pedigree family member. Genomic DNA was isolated from peripheral leukocytes using standard methods. Targeted next‐generation sequencing and Sanger sequencing were performed to find the pathogenic mutation in this family. Minigene assays were used to verify whether the novel intronic mutation SLC26A4c.765+4A>G influenced mRNA splicing. Results Hearing loss in the patients with EVA was diagnosed using auditory tests and imaging examinations. Two pathogenic mutations, c.765+4A>G and c.919‐2A>G were detected in SLC26A4. In vitro minigene analysis confirmed that c.765+4A>G variant could cause aberrant splicing, resulting in skipping over exon 6. Conclusions The SLC26A4c.765+4A>G mutation is the causative variant in the Chinese family with EVA. Particular attention should be paid to intronic variants.

In cystic fibrosis (CF), defects in the CF transmembrane conductance regulator (CFTR) channel lead to an acidic airway surface liquid (ASL), which compromises innate defence mechanisms, predisposing to pulmonary failure. Restoring ASL pH is a potential therapy for people with CF, particularly for those who cannot benefit from current highly effective modulator therapy. However, we lack a comprehensive understanding of the complex mechanisms underlying ASL pH regulation. The calcium-activated chloride channel, TMEM16A, and the anion exchanger, SLC26A4, have been proposed as targets for restoring ASL pH, but current results are contradictory and often utilise nonphysiological conditions. To provide better evidence for a role of these two proteins in ASL pH homeostasis, we developed an efficient CRISPR-Cas9- based approach to knock-out (KO) relevant transporters in primary airway basal cells lacking CFTR and then measured dynamic changes in ASL pH under thin-film conditions in fully differentiated airway cultures, which better simulate the in vivo situation. Unexpectantly, we found that both proteins regulated steady-state as well as agonist-stimulated ASL pH, but only under inflammatory conditions. Furthermore, we identified two Food and Drug Administration (FDA)-approved drugs which raised ASL pH by activating SLC26A4. While we identified a role for SLC26A4 in fluid absorption, KO had no effect on cyclic adenosine monophosphate (cAMP)-stimulated fluid secretion in airway organoids. Overall, we have identified a role of TMEM16A in ASL pH homeostasis and shown that both TMEM16A and SLC26A4 could be important alternative targets for ASL pH therapy in CF, particularly for those people who do not produce any functional CFTR. [ABSTRACT FROM AUTHOR]

Enlarged vestibular aqueduct is an autosomal genetic disease mainly caused by mutations in the SLC26A4 gene and includes non-syndromic and syndromic types. This study aimed to identify genetic defects in a Chinese patient with nonsyndromic enlarged vestibular aqueduct (NSEVA) and to investigate the impact of variants on the severity of non-syndromic enlarged vestibular aqueduct. A male patient with NSEVA, aged approximately 6 years, was recruited for this study. The clinical characteristics and results of auxiliary examinations, including laboratory and imaging examinations, were collected, and 127 common hereditary deafness genes were detected by chip capture high-throughput sequencing. Protein structure predictions, the potential impact of mutations, and multiple sequence alignments were analyzed in silico. Compound heterozygote mutations c.1523_ 1528delinsAC (p.Thr508Asnfs*3) and c.422T>C (p.Phe141Ser) in the SLC26A4 gene were identified. The novel frameshift mutation c.1523_1528delinsAC produces a severely truncated pendrin protein, and c.422T>C has been suggested to be a disease-causing mutation. Therefore, this study demonstrates that the novel mutation c.1523_1528delinsAC in compound heterozygosity with c.422T>C in the SLC26A4 gene is likely to be the cause of NSEVA. Cochlear implants are the preferred treatment modality for patients with NSEVA and severe-to-profound sensorineural hearing loss Genetic counseling and prenatal diagnosis are essential for early diagnosis. These findings expand the mutational spectrum of SLC26A4 and improve our understanding of the molecular mechanisms underlying NSEVA. [ABSTRACT FROM AUTHOR]

Solute carrier family 26 member 4 (SLC26A4) is a member of the SLC26A transporter family and is expressed in various tissues, including the airway epithelium, kidney, thyroid, and tumors. It transports various ions, including bicarbonate, chloride, iodine, and oxalate. As a multiple-ion transporter, SLC26A4 is involved in the maintenance of hearing function, renal function, blood pressure, and hormone and pH regulation. In this review, we have summarized the various functions of SLC26A4 in multiple tissues and organs. Moreover, the relationships between SLC26A4 and other channels, such as cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, and sodium chloride cotransporter, are highlighted. Although the modulation of SLC26A4 is critical for recovery from malfunctions of various organs, development of specific inducers or agonists of SLC26A4 remains challenging. This review contributes to providing a better understanding of the role of SLC26A4 and development of therapeutic approaches for the SLC26A4-associated hearing loss and SLC26A4-related dysfunction of various organs.

Background: Hearing loss is found in more than 5 % of cases worldwide. Hearing loss is divided into three types: Sensorineural hearing loss, Combined hearing loss and Conductive hearing loss. Among them, no less than 50 % of pediatric cases of sensorineural hearing loss are genetic. In Henan, China, there are no statistics on the allele frequency of deafness gene variants. Methods: We divided 2178 subjects enrolled at the Third Affiliated Hospital of Zhengzhou College from January 2019 to March 2021 into a hearing loss group and a normal control group. We performed array and pathogenicity classification for screening the 15 deafness gene variants, calculated and compared the allele frequency of the deafness gene variants, and then compared the hearing loss diagnosis rate between the hearing loss group and the normal control group. Results: We found that in the hearing loss group, the overall allele frequency of all detected variants was 16.6 %. Comparative analysis showed that the allele frequencies of GJB2 c.235delC variant, GJB3 c.538C > T variant and SLC26A4 c.919-2A > G variant were significantly higher than those of the East Asian population average in the gnomAD database. At the same time, our study confirmed that GJB3 c.538C > T variant may not be the disease-causing variant of hearing loss. Conclusions: These results support genetic counseling and rational prediction of risk for deafness.

Background: The primary pathological alterations of Pendred syndrome are endolymphatic pH acidification and luminal enlargement of the inner ear. However, the molecular contributions of specific cell types remain poorly characterized. Therefore, we aimed to identify pH regulators in pendrin-expressing cells that may contribute to the homeostasis of endolymph pH and define the cellular pathogenic mechanisms that contribute to the dysregulation of cochlear endolymph pH in Slc26a4−/− mice. Methods: We used single-cell RNA sequencing to identify both Slc26a4-expressing cells and Kcnj10-expressing cells in wild-type (WT, Slc26a4+/+) and Slc26a4−/− mice. Bioinformatic analysis of expression data confirmed marker genes defining the different cell types of the stria vascularis. In addition, specific findings were confirmed at the protein level by immunofluorescence. Results: We found that spindle cells, which express pendrin, contain extrinsic cellular components, a factor that enables cell-to-cell communication. In addition, the gene expression profile informed the pH of the spindle cells. Compared to WT, the transcriptional profiles in Slc26a4−/− mice showed downregulation of extracellular exosome-related genes in spindle cells. Immunofluorescence studies in spindle cells of Slc26a4−/− mice validated the increased expression of the exosome-related protein, annexin A1, and the clathrin-mediated endocytosis-related protein, adaptor protein 2. Conclusion: Overall, cell isolation of stria vascularis from WT and Slc26a4−/− samples combined with cell type-specific transcriptomic analyses revealed pH-dependent alternations in spindle cells and intermediate cells, inspiring further studies into the dysfunctional role of stria vascularis cells in SLC26A4-related hearing loss. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study aimed to provide statistical data support for the development of thyroid phenotype-related follow-up and reference for follow-up duration and project selection by analyzing the clinical characteristics of thyroid phenotype in Pendred syndrome (PDS) based on multiple databases. MATERIALS AND METHODS: PDS-related pathogenic or possibly/pathogenic mutations were searched by Deafness Variation Database (DVD), ClinVar, and PubMed databases, the mutation sites were counted and the characteristics and thyroid phenotypes were analyzed. RESULTS: The median age of hearing phenotype onset in PDS cases reported in multiple databases was 1.0 (1.0, 2.0) years, the median age of thyroid phenotype onset was 14.5 (5.8, 21.0) years, and the median age that thyroid phenotype was more delayed than hearing phenotype was 10.0 (4.0, 17.0) years. There were significant differences in the distribution of onset time between the two phenotypes (Z=-4.560, p<0.01). In these patients, the positive rates of goiter, thyroid nodules, abnormal thyroid function, and perchlorate discharge test (PDT) were 78%, 78%, 69%, and 78%, respectively. Moreover, the number of thyroid phenotype-positive items in the genotype group with frameshift mutation was not significantly higher than that in the group without frameshift mutation (Z=-1.452, p=0.147). CONCLUSIONS: The early missed diagnosis of PDS may be due to the late onset of thyroid phenotype and the non-100% positive rate of examination items. Therefore, multi-item follow-up of the thyroid gland into adulthood will benefit patients. At present, the relationship between genotype and phenotype is still unclear, and prognosis cannot be determined according to genotype. [ABSTRACT FROM AUTHOR]

Objective To explore the effect of miR-26a-5p in regulating SLC26A4 to amiliorate hearing loss, and to detect the expression changes of miR-26a-5p and SLC26A4 in deaf mice and hearing loss mice. Methods A mouse hearing loss model and a mouse deafness model were constructed, and the auditory brainstem response test was used to detect the hearing in the right ear of mice to determine whether the models were successfully constructed. qPCR test was used to detect the relative expression of miR-26a-5p and SLC26A4 after hearing loss and deafness in mice were established. The specific site of miR-26a-5p targeting binding to SLC26A4 was predicted at TargetScan website. The interference and overexpression vector of miR-26a-5p and SLC26A4 were injected，, and the expression changes of miR-26a-5p and SLC26A4 were detected. Results After hearing loss and deafness were established, the expression of miR-26a-5p was significantly decreased (P < 0.05), while the expression of SLC26A4 was significantly increased (P < 0.05). After antagomir injection, miR-26a-5p was significantly down-regulated (P = 0.047)，while SLC26A4 was significantly up-regulated (P = 0.014)；and the hearing threshold of mice decreased significantly (P < 0.05)，but the result was just the opposite after injection of miR-26a-5p agomir. Conclusion miR-26a-5p can ameliorate hearing loss through SLC26A4 and thus decelerate the development of deafness. [ABSTRACT FROM AUTHOR]

Pathogenic variants in the SLC26A4 gene leading to nonsyndromic recessive deafness (DFNB4), or Pendred syndrome, are some of the most common causes of hearing loss worldwide. Earlier, we found a high proportion of SLC26A4-related hearing loss with prevailing pathogenic variant c.919-2A>G (69.3% among all mutated SLC26A4 alleles that have been identified) in Tuvinian patients belonging to the indigenous Turkic-speaking Siberian people living in the Tyva Republic (Southern Siberia, Russia), which implies a founder effect in the accumulation of c.919-2A>G in Tuvinians. To evaluate a possible common origin of c.919-2A>G, we genotyped polymorphic STR and SNP markers, intragenic and flanking SLC26A4, in patients homozygous for c.919-2A>G and in healthy controls. The common STR and SNP haplotypes carrying c.919-2A>G were revealed, which convincingly indicates the origin of c.919-2A>G from a single ancestor, supporting a crucial role of the founder effect in the c.919-2A>G prevalence in Tuvinians. Comparison analysis with previously published data revealed the identity of the small SNP haplotype (~4.5 kb) in Tuvinian and Han Chinese carriers of c.919-2A>G, which suggests their common origin from founder chromosomes. We assume that c.919-2A>G could have originated in the geographically close territories of China or Tuva and subsequently spread to other regions of Asia. In addition, the time intervals of the c.919-2A>G occurrence in Tuvinians were roughly estimated. [ABSTRACT FROM AUTHOR]

Pendrin and prestin are evolutionary-conserved membrane proteins that are essential for normal hearing. Dysfunction of these proteins results in hearing loss in humans, and numerous deafness-associated pendrin and prestin variants have been identified in patients. However, the pathogenic impacts of many of these variants are ambiguous. Here, we report results from our ongoing efforts to experimentally characterize pendrin and prestin variants using in vitro functional assays. With previously established fluorometric anion transport assays, we determined that many of the pendrin variants identified on transmembrane (TM) 10, which contains the essential anion binding site, and on the neighboring TM9 within the core domain resulted in impaired anion transport activity. We also determined the range of functional impairment in three deafness-associated prestin variants by measuring nonlinear capacitance (NLC), a proxy for motor function. Using the results from our functional analyses, we also evaluated the performance of AlphaMissense (AM), a computational tool for predicting the pathogenicity of missense variants. AM prediction scores correlated well with our experimental results; however, some variants were misclassified, underscoring the necessity of experimentally assessing the effects of variants. Together, our experimental efforts provide invaluable information regarding the pathogenicity of deafness-associated pendrin and prestin variants.

Pendrin is a transmembrane chloride/anion antiporter that is strongly upregulated in the airways in rhinoviral infection, asthma, cystic fibrosis and chronic rhinosinusitis. Based on its role in the regulation of airway surface liquid depth, pendrin inhibitors have potential indications for treatment of inflammatory airways diseases. Here, a completely regioselective route to tetrahydro-pyrazolopyridine pendrin inhibitors based on 1,3-diketone and substituted hydrazine condensation was been developed. Structure-activity relationships at the tetrahydropyridyl nitrogen were investigated using a focused library, establishing the privileged nature of N-phenyl ureas and improving inhibitor potency by greater than 2-fold.

Abstract Background To investigate the genetic causes of hearing loss in patients with enlarged vestibular aqueduct (EVA), the SLC26A4-related genotypes and phenotypes were analyzed. SLC26A4 gene is closely associated with EVA and its homozygous mutations or compound heterozygous mutations may cause deafness and strongly affect quality of life. Methods The patients who came to our hospital for hearing test and accompanied by bilateral hearing abnormalities were collected for fifteen deafness-related gene mutations detection. Those who are positive will be verified by Sanger sequencing, combined with family history, hearing test, and computerized tomography (CT) of the temporal bone, aiming to diagnose the enlarged vestibular aqueducts. Whole-exome sequencing were performed when necessary. Results Our patient failed hearing screening on both sides twice, and EVA (> 1.5 mm) was diagnosed by CT. This study has identified a novel missense mutation in the SLC26A4 gene, c.2069T>A, which in compound heterozygosity with c.1174A>T is likely to be the cause of hearing loss. The novel heterozygous c.2069T>A mutation of SLC26A4 gene has been submitted to Clinvar with Variation ID 1,048,780. Conclusion Our findings expand the gene mutation spectrum of SLC26A4 and provide additional knowledge for diagnosis and genetic counseling associated with EVA-induced hearing loss.

Abstract Background Homologous recombination deficiency (HRD) is closely associated with patient prognosis and treatment options in prostate cancer (PCa). However, there is a lack of quantitative indicators related to HRD to predict the prognosis of PCa accurately. Methods We screened HRD-related genes based on the HRD scores and constructed an HRD cluster system to explore different clinicopathological, genomic, and immunogenomic patterns among the clusters. A risk signature, HRDscore, was established and evaluated by multivariate Cox regression analysis. We noticed that SLC26A4, a model gene, demonstrated unique potential to predict prognosis and HRD in PCa. Multi-omics analysis was conducted to explore its role in PCa, and the results were validated by qRT-PCR and immunohistochemistry. Results Three HRD clusters were identified with significant differences in patient prognosis, clinicopathological characteristics, biological pathways, immune infiltration characteristics, and regulation of immunomodulators. Further analyses revealed that the constructed HRDscore system was an independent prognostic factor of PCa patients with good stability. Finally, we identified a single gene, SLC26A4, which significantly correlated with prognosis in three independent cohorts. Importantly, SLC26A4 was confirmed to distinguish PCa (AUC for mRNA 0.845; AUC for immunohistochemistry score 0.769) and HRD (AUC for mRNA 0.911; AUC for immunohistochemistry score 0.689) at both RNA and protein levels in our cohort. Conclusion This study introduces HRDscore to quantify the HRD pattern of individual PCa patients. Meanwhile, SLC26A4 is a novel biomarker and can reasonably predict the prognosis and HRD in PCa.

A wide spectrum of SLC26A4 mutations causes Pendred syndrome and enlarged vestibular aqueduct, both associated with sensorineural hearing loss (SNHL). A splice-site mutation, c.919-2A>G (A-2G), which is common in Asian populations, impairs the 3′ splice site of intron 7, resulting in exon 8 skipping during pre-mRNA splicing and a subsequent frameshift that creates a premature termination codon in the following exon. Currently, there is no effective drug treatment for SHNL. For A-2G-triggered SNHL, molecules that correct mis-splicing of the mutant hold promise to treat the disease. Antisense oligonucleotides (ASOs) can promote exon inclusion when targeting specific splicing silencers. Here, we systematically screened a large number of ASOs in a minigene system and identified a few that markedly repressed exon 8 skipping. A lead ASO, which targets a heterogeneous nuclear ribonucleoprotein (hnRNP) A1/A2 intronic splicing silencer (ISS) in intron 8, promoted efficient exon 8 inclusion in cultured peripheral blood mononuclear cells derived from two homozygous patients. In a partially humanized Slc26a4 A-2G mouse model, two subcutaneous injections of the ASO at 160 mg/kg significantly rescued exon 8 splicing in the liver. Our results demonstrate that the ISS-targeting ASO has therapeutic potential to treat genetic hearing loss caused by the A-2G mutation in SLC26A4.

SLC26A4 gene mutations related to hearing loss patients can obtain good hearing and speech rehabilitation effects after cochlear implantation (CI). To explore the long-term rehabilitative outcomes of CI in patients with different SLC26A4 mutation groups. Clinical data of 71 patients with SLC26A4 gene mutations who received CI in the Second Hospital of Lanzhou University from 2012 to 2015 were retrospectively reviewed. According to the genetic test results, use One-way ANOVA analysis to compare the differences in auditory results, categories of auditory performance (CAP) and speech intelligibility rating (SIR) index questionnaire scores and speech recognition rates among different groups in 4-5 years after CI. Compared with other genotypes of SLC26A4, the patients with homozygous mutation of c.919-2A > G in SLC26A4 had better hearing aid threshold at 500 Hz and better recognition rates of Yangyang words than other monoallelic mutation groups after CI (p <.05). The most common hot spot mutation of SLC26A4 gene is c.919-2A > G. The patients with homozygous mutation of c.919-2A > G in SLC26A4 gene had partly better hearing and speech rehabilitation than other monoallelic mutation groups after CI. [ABSTRACT FROM AUTHOR]

Background: Nonsyndromic autosomal recessive hearing loss (DFNB) is an etiologically heterogeneous disorder group showing a wide spectrum of onset ages and severity. DFNB genes are very diverse in their types and functions, making molecular diagnosis difficult. DFNB is particularly frequent in Pakistan, which may be partly due to consanguinity. Objective: This study was performed to determine the genetic causes in Pakistani DFNB families with prelingual onset and to establish genotype-phenotype correlation. Methods: Whole exome sequencing and subsequent genetic analysis were performed for 11 Pakistani DFNB families including eight consanguineous families. Results: We identified eight pathogenic or likely pathogenic mutations in LOXHD1, GJB2, SLC26A4, MYO15A, and TMC1 from six families. The GJB2 mutations were identified in two families each with compound heterozygous mutations and a homozygous mutation. The compound heterozygous mutations in LOXHD1 ([p.D278Y] + [p.D1219E]) and GJB2 [p.M1?] + [p.G12Vfs*2]) were novel. The four missense or start-loss mutations were located at well conserved residues, and most in silico analysis predicted their pathogenicity. In addition to causative mutations, we found compound heterozygous mutations in PTPRQ as variants of uncertain significance. Conclusion: This study identified biallelic mutations as the underlying cause of early onset DFNB in six Pakistani families. This study will be helpful in providing an exact molecular diagnosis and treatment of prelingual onset deafness patients. [ABSTRACT FROM AUTHOR]

SLC26A4 is one of the most common genes causing autosomal recessive non-syndromic sensorineural hearing loss (SNHL). It has been reported to cause Pendred Syndrome (PDS) and DFNB4 which is deafness with enlarged vestibular aqueduct (EVA). However, mutated SLC26A4 is not conclusive for having either DFNB4 or PDS. Three unrelated Jordanian families consisting of eight affected individuals with congenital bilateral hearing loss (HL) participated in this study. Whole-exome and Sanger sequencing were performed to investigate the underlying molecular etiology of HL. Further clinical investigations, including laboratory blood workup for the thyroid gland, CT scan for the temporal bone, and thyroid ultrasound were performed. Three disease-causing variants were identified in SLC26A4 in the three families, two of which were novel. Two families had a novel pathogenic homozygous splice-site accepter variant (c.165-1G>C), while the third family had compound heterozygous pathogenic variants (c.1446G>A; p.Trp482* and c.304G>A; p.Gly102Arg). Our approach helped in redirecting the diagnosis of several affected members of three different families from non-syndromic HL to syndromic HL. Two of the affected individuals had typical PDS, one had DFNB4, while the rest had atypical PDS. Our work emphasized the intra- and inter-familial variability of SLC26A4-related phenotypes. In addition, we highlighted the variable phenotypic impact of SLC26A4 on tailoring a personalized healthcare management. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Defects in the human solute carrier family 26 member 4 (SLC26A4) gene are reported to be one of the causes of congenital hypothyroidism (CH). We aimed to identify SLC26A4 mutations in Chinese patients with CH and analyze the function of the mutations. METHODS: Patients with primary CH were screened for 21 CH candidate genes mutations by targeted next-generation sequencing. All the exons and exon-intron boundaries of SLC26A4 were identified and analyzed. The function of six missense mutation in SLC26A4 were further investigated in vitro. RESULTS: Among 273 patients with CH, seven distinct SLC26A4 heterozygous mutations (p.S49R, p.I363L, p.R409H, p.T485M, p.D661E, p.H723R, c.919-2A>G) were identified in 10 patients (3.66%, 10/273). In vitro experiments showed that mutation p.I363L, p.R409H, p.H723R affect the membrane location and ion transport of SLC26A4, while p.S49R did not. Mutation p.T485M and p.D661E only affected ion transport, but had no effect on the membrane location. DISCUSSION AND CONCLUSION: The prevalence of SLC26A4 mutations was 3.66% in Chinese patients with CH. Five mutations (p.I363L, p.R409H, p.T485M, p.D661E and p.H723R) impaired the membrane location or ion transport function of SLC26A4, suggesting important roles for Ile363, Arg409, Thr485, Asp661, and His723 residues in SLC26A4 function. As all variants identified were heterozygous, the pathogenesis of these patients cannot be explained, and the pathogenesis of these patients needs further study

Abstract Background The enlarged vestibular aqueduct (EVA), associated with mutations in the SLC26A4 gene, characterized by non-syndromic hearing loss, is an autosomal recessive disorder. Here, we intended to investigate genetic causes of hearing loss in a Han Chinese man. Method First, whole-exome sequencing was performed to identify the gene mutations responsible for hearing loss in the proband. Sanger sequencing was used to verify the candidate mutations detected in the family. Next, we collected blood samples and clinical data from the three-generation pedigree. Finally, SLC26A4 mRNA and protein expression levels were detected by qPCR and western blotting. Result The proband suffered from bilateral progressive sensorineural hearing loss with EVA. The sequence analysis of SLC26A4 revealed that the proband and his sister both harbored a compound heterozygous mutation of c.2168A > G/c.2029C > T, inherited from their father and mother respectively. c.2029C > T mutation has not been recorded in the relevant literature previously. Relative mRNA levels of the SLC26A4 gene in individuals carrying a compound heterozygous mutation were significantly lower compared to a heterozygous mutation. SLC26A4 protein levels of 293t cells which transfected with recombinant plasmids [GV219-SLC26A4-mut (c.2029C > T) and GV219-SLC26A4-mut (c.2168A > G/c.2029C > T)] were significantly lower than normal control recombinant plasmids (GV219-SLC26A4-wt). Conclusion This study found a novel heterozygous mutation c.2029 (exon17) C > T compound with c.2168 (exon19) A > G in the SLC26A4 gene in a patient with EVA. The c.2029 (exon17) C > T mutation is proved to be pathogenic. This finding broadens the spectrum of variants in SLC26A4 gene.

Abstract Background Landau-Kleffner syndrome (LKS) is an acquired aphasia and electroencephalogram (EEG) abnormalities mainly in temporoparietal areas. SLC26A4 mutations can cause hearing loss associated with enlarged vestibular aqueduct (EVA). Case presentations We report a case of LKS in a 5-year-old boy with non-syndromic EVA due to homozygous mutations of c.919-2A>G (IVS7-2A>G) in SLC26A4. He had normal language development before 2 years old. At the age of 2.5 years, he was admitted to the hospital due to remarkable language delay, and diagnosed with hearing loss with EVA. The seizures started at 4.4 years of age and EEG recording showed electrical status epilepticus during sleep (ESES) with a posterior-temporal predominance. He received cochlear implantation in the right ear at 4.7 years of age, which improved his hearing and language skills. The nocturnal focal motor seizures recurred at 4.9 years of age. Then a remarkable inability to respond to calls and reduction in spontaneous speech were noticed. He was treated with methylprednisolone at 5 years old, which controlled the seizures, suppressed ESES, and remarkably improved the language ability. The absence of seizures maintained until the last follow-up at 5.3 years of age, with further improvements in EEG recording and language ability. Conclusions The co-existence of LKS and hearing loss caused by SLC26A4 mutations increases the difficulty of LKS diagnosis, especially in the presence of hearing loss and impaired language skills. EEG discharges predominantly in temporoparietal areas, the occurrence of ESES, and language improvement after antiepileptic medications are potential indicators for LKS diagnosis.

The SLC26A4 gene encodes the transmembrane protein pendrin, which is involved in the ion transport of chloride (Cl-), iodide (I-) or bicarbonate (HCO3-). Mutations in the SLC26A4 gene alter the structure and (or) function of pendrin, which are closely related to Pendred syndrome. What’s more, researchers have demonstrated in vitro that mutations of SLC26A4 cause acidification of airway surface fluid (ASL), reduce airway defense, and increase the thickness of ASL. In the context of infection, it may lead to chronic inflammation, destruction of airway wall architecture and bronchiectasis. However, there is no case report of bronchiectasis caused by SLC26A4 gene mutations. Here, we describe the first case of Pendred syndrome and non-cystic fibrosis bronchiectasis in a child possibly caused by SLC26A4 mutations. We remind clinicians to pay attention to the possibility of bronchiectasis in patients with SLC26A4 gene mutations.

Screening pathogenic variants in the SLC26A4 gene is an important part of molecular genetic testing for hearing loss (HL) since they are one of the common causes of hereditary HL in many populations. However, a large size of the SLC26A4 gene (20 coding exons) predetermines the difficulties of its complete mutational analysis, especially in large samples of patients. In addition, the regional or ethno-specific prevalence of SLC26A4 pathogenic variants has not yet been fully elucidated, except variants c.919-2A>G and c.2168A>G (p.His723Arg), which have been proven to be most common in Asian populations. We explored the distribution of currently known pathogenic and likely pathogenic (PLP) variants across the SLC26A4 gene sequence presented in the Deafness Variation Database for the selection of potential diagnostically important parts of this gene. As a result of this bioinformatic analysis, we found that molecular testing ten SLC26A4 exons (4, 6, 10, 11, 13–17 and 19) with flanking intronic regions can provide a diagnostic rate of 61.9% for all PLP variants in the SLC26A4 gene. The primary sequencing of these SLC26A4 regions may be applied as an initial effective diagnostic testing in samples of patients of unknown ethnicity or as a subsequent step after the targeted testing of already-known ethno- or region-specific pathogenic SLC26A4 variants. [ABSTRACT FROM AUTHOR]

The SLC26A4 gene, which encodes the anion exchanger pendrin, is involved in determining syndromic (Pendred syndrome) and non-syndromic (DFNB4) autosomal recessive hearing loss. SLC26A4 c.349C>T, p.L117F is a relatively common allele in the Ashkenazi Jewish community, where its minor allele frequency is increased compared to other populations. Although segregation and allelic data support the pathogenicity of this variant, former functional tests showed characteristics that were indistinguishable from those of the wild-type protein. Here, we applied a triad of cell-based assays, i.e., measurement of the ion transport activity by a fluorometric method, determination of the subcellular localization by confocal microscopy, and assessment of protein expression levels, to conclusively assign or exclude the pathogenicity of SLC26A4 p.L117F. This protein variant showed a moderate, but significant, reduction in ion transport function, a partial retention in the endoplasmic reticulum, and a strong reduction in expression levels as a consequence of an accelerated degradation by the Ubiquitin Proteasome System, all supporting pathogenicity. The functional and molecular features of human pendrin p.L117F were recapitulated by the mouse ortholog, thus indicating that a mouse carrying this variant might represent a good model of Pendred syndrome/DFNB4. [ABSTRACT FROM AUTHOR]

SLC26A4 causes Pendred syndrome (PS) and nonsyndromic hearing loss. PS is distinguished based on perchlorate discharge test abnormality, goiter, and hypothyroidism in some patients. The pathophysiology of thyroid dysfunction in PS differs from that of autoimmune thyroid disease, in that it is considered to be caused by an iodide organification defect. It is believed that both diseases may incidentally coexist, and that SLC26A4 may play an important role in the etiology of autoimmune thyroid disease. Herein, we describe a case of a girl with hearing loss who had two pathogenic SLC26A4 variants and tested positive for thyroid peroxidase (TPO) antibody. She was diagnosed with hearing loss and vestibular aqueduct enlargement at the age of 4 yr. Deafness gene screening revealed two pathogenic SLC26A4 variants. As SLC26A4 variants can cause PS, the patient underwent thorough thyroid examination. Her thyroid gland was within the physiological range of mild enlargement. Although thyroid function test results were normal, the patient tested positive for TPO antibody. The patient was diagnosed with "suspected PS" and "suspected Hashimoto's thyroiditis," both of which increase the risk of developing hypothyroidism. Evaluating the comorbidity of Hashimoto's thyroiditis with the SLC26A4 variant in terms of complications is critical., Competing Interests: The authors have no competing interests to declare., (2024©The Japanese Society for Pediatric Endocrinology.)

After GJB2, SLC26A4 is the second most common contributor to autosomal recessive nonsyndromic hearing loss (ARNSHL) worldwide. In this study, we used Exome Sequencing (ES) to present a village with 31 individuals affected by hereditary hearing loss (HHL) in southeastern Iran near the border of Pakistan. The village harbored the known pathogenic missense SLC26A4 (NM&#95;000441.2):c.716T>A (p.Val239Asp) mutation, which has a founder effect attributed to Pakistan, Iran's southeastern neighbor. Our findings, in addition to unraveling the molecular cause of non-syndromic hearing loss in these patients and further confirming the common ancestry and migration story between the people of this region and Pakistan, provide further insight into the genetic background of this region and highlight the importance of understanding the mutation spectrum of GJB2 and SLC26A4 in different regions to choose cost-effective strategies for molecular genetic testing., (© 2024 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.)

Background: Homologous recombination deficiency (HRD) is closely associated with patient prognosis and treatment options in prostate cancer (PCa). However, there is a lack of quantitative indicators related to HRD to predict the prognosis of PCa accurately.Methods: We screened HRD-related genes based on the HRD scores and constructed an HRD cluster system to explore different clinicopathological, genomic, and immunogenomic patterns among the clusters. A risk signature, HRDscore, was established and evaluated by multivariate Cox regression analysis. We noticed that SLC26A4, a model gene, demonstrated unique potential to predict prognosis and HRD in PCa. Multi-omics analysis was conducted to explore its role in PCa, and the results were validated by qRT-PCR and immunohistochemistry.Results: Three HRD clusters were identified with significant differences in patient prognosis, clinicopathological characteristics, biological pathways, immune infiltration characteristics, and regulation of immunomodulators. Further analyses revealed that the constructed HRDscore system was an independent prognostic factor of PCa patients with good stability. Finally, we identified a single gene, SLC26A4, which significantly correlated with prognosis in three independent cohorts. Importantly, SLC26A4 was confirmed to distinguish PCa (AUC for mRNA 0.845; AUC for immunohistochemistry score 0.769) and HRD (AUC for mRNA 0.911; AUC for immunohistochemistry score 0.689) at both RNA and protein levels in our cohort.Conclusion: This study introduces HRDscore to quantify the HRD pattern of individual PCa patients. Meanwhile, SLC26A4 is a novel biomarker and can reasonably predict the prognosis and HRD in PCa. [ABSTRACT FROM AUTHOR]

Background: To investigate the genetic causes of hearing loss in patients with enlarged vestibular aqueduct (EVA), the SLC26A4-related genotypes and phenotypes were analyzed. SLC26A4 gene is closely associated with EVA and its homozygous mutations or compound heterozygous mutations may cause deafness and strongly affect quality of life. Methods: The patients who came to our hospital for hearing test and accompanied by bilateral hearing abnormalities were collected for fifteen deafness-related gene mutations detection. Those who are positive will be verified by Sanger sequencing, combined with family history, hearing test, and computerized tomography (CT) of the temporal bone, aiming to diagnose the enlarged vestibular aqueducts. Whole-exome sequencing were performed when necessary. Results: Our patient failed hearing screening on both sides twice, and EVA (> 1.5 mm) was diagnosed by CT. This study has identified a novel missense mutation in the SLC26A4 gene, c.2069T>A, which in compound heterozygosity with c.1174A>T is likely to be the cause of hearing loss. The novel heterozygous c.2069T>A mutation of SLC26A4 gene has been submitted to Clinvar with Variation ID 1,048,780. Conclusion: Our findings expand the gene mutation spectrum of SLC26A4 and provide additional knowledge for diagnosis and genetic counseling associated with EVA-induced hearing loss. [ABSTRACT FROM AUTHOR]

• Genetic etiology was clarified in 54 families, with a positive rate of 48%. • 19 novel P/LP variants and 22 VUS variants were identified. All of these findings broadened the mutation spectrum of hearing loss genes. Hearing loss is a group of diseases with high genetic heterogeneity. About 160 genes have been reported to be associated with hereditary hearing loss. 113 families with hearing loss were collected, and WES was used to detect SNV, InDel, CNV and mitochondrial gene variants. For some probands with negative WES test results, the copy number of STRC and OTOA were determined by using real-time fluorescence quantitative PCR. Pathogenic or likely pathogenic variants were found in 54 probands, of which 98% (53/54) were SNVs or InDels and 2% (1/54) were CNVs, a positive rate of 48%. 16 families (14%) were detected with candidate variants of uncertain significance. 19 novel pathogenic or likely pathogenic variants and 22 candidate variants of uncertain significance were identified in this study. The most common hearing loss gene in the families was GJB2 , accounting for 28% (15/53), followed by SLC26A4 and MYO15A , accounting for 21% (11/53) and 11% (6/53), respectively. Heterozygous gene deletion was detected in 3 probands, including 2 with STRC and 1 with OTOA in 43 families with WES negative test. Genetic etiology was clarified in 54 families. All of these findings broadened the mutation spectrum of hearing loss genes, thus providing new variant information for the future diagnosis of patients with hearing loss. [ABSTRACT FROM AUTHOR]

Autism spectrum disorder (ASD) is an early-onset neurodevelopmental disorder in which genetics play a major role. Molecular diagnosis may lead to a more accurate prognosis, improved clinical management, and potential treatment of the condition. Both copy number variations (CNVs) and single nucleotide variations (SNVs) have been reported to contribute to the genetic etiology of ASD. The effectiveness and validity of clinical targeted panel sequencing (CTPS) designed to analyze both CNVs and SNVs can be evaluated in different ASD cohorts. CTPS was performed on 573 patients with the diagnosis of ASD. Medical records of positive CTPS cases were further reviewed and analyzed. Additional medical examinations were performed for a group of selective cases. Positive molecular findings were confirmed by orthogonal methods. The overall positive rate was 19.16% (109/569) in our cohort. About 13.89% (79/569) and 4.40% (25/569) of cases had SNVs only and CNVs only findings, respectively, while 0.9% (5/569) of cases had both SNV and CNV findings. For cases with SNVs findings, the SHANK3 gene has the greatest number of reportable variants, followed by gene MYT1L. Patients with MYT1L variants share common and specific clinical characteristics. We found a child with compound heterozygous SLC26A4 variants had an enlarged vestibular aqueduct syndrome and autistic phenotype. Our results showed that CTPS is an effective molecular diagnostic tool for ASD. Thorough clinical and genetic evaluation of ASD can lead to more accurate diagnosis and better management of the condition. [ABSTRACT FROM AUTHOR]

Background: The enlarged vestibular aqueduct (EVA), associated with mutations in the SLC26A4 gene, characterized by non-syndromic hearing loss, is an autosomal recessive disorder. Here, we intended to investigate genetic causes of hearing loss in a Han Chinese man. Method: First, whole-exome sequencing was performed to identify the gene mutations responsible for hearing loss in the proband. Sanger sequencing was used to verify the candidate mutations detected in the family. Next, we collected blood samples and clinical data from the three-generation pedigree. Finally, SLC26A4 mRNA and protein expression levels were detected by qPCR and western blotting. Result: The proband suffered from bilateral progressive sensorineural hearing loss with EVA. The sequence analysis of SLC26A4 revealed that the proband and his sister both harbored a compound heterozygous mutation of c.2168A > G/c.2029C > T, inherited from their father and mother respectively. c.2029C > T mutation has not been recorded in the relevant literature previously. Relative mRNA levels of the SLC26A4 gene in individuals carrying a compound heterozygous mutation were significantly lower compared to a heterozygous mutation. SLC26A4 protein levels of 293t cells which transfected with recombinant plasmids [GV219-SLC26A4-mut (c.2029C > T) and GV219-SLC26A4-mut (c.2168A > G/c.2029C > T)] were significantly lower than normal control recombinant plasmids (GV219-SLC26A4-wt). Conclusion: This study found a novel heterozygous mutation c.2029 (exon17) C > T compound with c.2168 (exon19) A > G in the SLC26A4 gene in a patient with EVA. The c.2029 (exon17) C > T mutation is proved to be pathogenic. This finding broadens the spectrum of variants in SLC26A4 gene. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study aimed to investigate the incidence of the hotspot mutations c.919-2A>G and c.2168A>G in SLC26A4 in the northwestern Chinese population. METHODS: A total of 2673 unrelated patients were recruited from northwestern China, and clinical information was obtained from all patients. Peripheral blood samples were acquired to detect the genotype of each patient by direct sequencing. Statistical analysis was conducted with Statistical Package for the Social Sciences 19.0 software. RESULTS: Overall, 118 patients (4.4%) were identified with biallelic mutations, including 84 (3.14%) homozygotes and 34 (1.27%) compound heterozygotes. Moreover, significant differences between Han and Uighur were identified regarding the frequencies of c.919-2A>G homozygous and biallelic mutations. CONCLUSION: This model for the rapid screening of hotspot mutations can identify the molecular cause for 4.4% of patients with severe to profound sensorineural hearing loss in northwestern China, and there may be distinctive hotspot mutations in different ethnic populations. [ABSTRACT FROM AUTHOR]

Abstract Background Congenital hearing loss is one of the most common birth defects. Early identification and management play a crucial role in improving patients’ communication and language acquisition. Previous studies demonstrated that genetic screening complements newborn hearing screening in clinical settings. Methods We developed a multiplex PCR amplicon sequencing assay to sequence the full coding region of the GJB2 gene, the most pathogenic variants of the SLC26A4 gene, and hotspot variants in the MT-RNR1 gene. The sensitivity, specificity, and reliability were validated via samples with known genotypes. Finally, a pilot study was performed on 300 anonymous dried blood samples. Results Of 103 samples with known genotypes, the multiplex PCR amplicon sequencing assay accurately identified all the variants, demonstrating a 100% sensitivity and specificity. The consistency is high in the analysis of the test–retest reliability and internal consistency reliability. In the pilot study, 12.3% (37/300) of the newborns were found to carry at least one pathogenic variant, including 24, 10, and 3 from the GJB2, SLC26A4, and MT-RNR1 gene, respectively. With an allele frequency of 2.2%, the NM_004004.6(GJB2):c.109G>A was the most prevalent variant in the study population. Conclusion The multiplex PCR amplicon sequencing assay is an accurate and reliable test to detect hearing loss variants in the GJB2, SLC26A4, and MT-RNR1 genes. It can be used to screen genetic hearing loss in newborns.