MPZL2-a common autosomal recessive deafness gene related to moderate sensorineural hearing loss in the Chinese population.

BACKGROUND: Mutations in MPZL2, the characteristic genetic etiology of autosomal recessive deafness loci 111 (DFNB111), cause non-syndromic and moderate sensorineural hearing loss. METHODS: In this study, we analyzed the phenotype and genotype of eight pedigrees consisting of 10 hearing loss patients with bi-allelic pathogenic or likely pathogenic variants in MPZL2. These patients were identified from a 3272 Chinese patient cohort who underwent genetic testing. RESULTS: Apart from symmetrical and moderate sensorineural hearing loss, the MPZL2-related phenotype was characterized by progressive hearing loss with variation in the onset age (congenital defect to onset at the young adult stage). We determined that in the Chinese population, the genetic load of MPZL2 defects was 0.24% (8/3272) in patients diagnosed with hearing loss and 7.02% (8/114) in patients diagnosed with hereditary moderate sensorineural hearing loss caused by STRC, OTOA, OTOG, OTOGL, TECTA, MPZL2 and others. Three known MPZL2 variants (c.220C > T (p.Gln74*), c.68delC (p.Pro23Leufs*2), c.463delG (p.Ala155Leufs*10)) and a novel start loss variant (c.3G > T (p.Met1?)) were identified. MPZL2 c.220C > T was identified as the hotspot variant in the Chinese population and even in East Asia compared with c.72delA (p.Ile24Metfs*22) in European and West Asia through allele frequency. CONCLUSIONS: We concluded that apart from moderate HL, progressive HL is another character of MPZL2-related HL. No specified variant was verified for the progression of HL, the penetrance and expressivity cannot be determined yet. A novel MPZL2 variant at the start codon was identified, enriching the variant spectrum of MPZL2. The hotspot variants of MPZL2 vary in different ethnicities. This study provides valuable data for the diagnosis, prognosis evaluation and genetic counseling of patients with moderate sensorineural hearing loss related to MPZL2.

A newborn male with Myhre syndrome, hearing loss, and complete syndactyly of fingers 3-4.

BACKGROUND: Myhre syndrome is a rare multisystem genetic disorder that is caused by de novo heterozygous gain-of-function variants in SMAD4. Patients with Myhre syndrome exhibit several phenotypes at different ages such as small size, autism, developmental delay, left-sided heart defects, and hearing loss and often have a characteristic facial appearance. The early clinical diagnosis of Myhre syndrome remains a major challenge, particularly in the first year of life. METHODS: A Chinese male infant with syndactyly of fingers, hypertelorism, short palpebral fissures, and short philtrum was enrolled into the ENT department of the Chinese PLA General Hospital. Whole exome sequencing analysis was used to detect the disease-causing variant. A literature review of Myhre syndrome was also performed. RESULTS: A recurrent de novo missense variant c.1498A > G p.I500V(p. Ile500Val) in SMAD4 was detected confirming the clinical diagnosis of Myhre syndrome at the age of 38 days. The infant appears to be the youngest reported case of Myhre syndrome. At 23-month follow-up, the affected infant has dysmorphic facial features, growth retardation, and previously undescribed complete syndactyly. Review the literatures noted several common features in Myhre syndrome patients including hearing loss (72.7%), characteristic facial features (26.0%-54.5%), finger and toe abnormalities (3.9%-48.1%), short stature (45.5%), and respiratory (30.0%) and cardiovascular problems (65.0%). CONCLUSIONS: Clinicians should have a low threshold to perform genetic testing on patients with features suggesting Myhre syndrome even in the first year of life. Although some individuals with Myhre syndrome have normal hearing, early onset or progressive hearing loss usually occur in one or both ears in most patients, with remarkable phenotypic heterogeneity. Syndactyly may be minor such as typical 2-3 toe involvement, or more complicated as was observed in our patient.

Addition of an affected family member to a previously ascertained autosomal recessive nonsyndromic hearing loss pedigree and systematic phenotype-genotype analysis of splice-site variants in MYO15A.

Pathogenic variants in MYO15A are known to cause autosomal recessive nonsyndromic hearing loss (ARNSHL), DFNB3. We have previously reported on one ARNSHL family including two affected siblings and identified MYO15A c.5964+3G > A and c.8375 T > C (p.Val2792Ala) as the possible deafness-causing variants. Eight year follow up identified one new affected individual in this family, who also showed congenital, severe to profound sensorineural hearing loss. By whole exome sequencing, we identified a new splice-site variant c.5531+1G > C (maternal allele), in a compound heterozygote with previously identified missense variant c.8375 T > C (p.Val2792Ala) (paternal allele) in MYO15A as the disease-causing variants. The new affected individual underwent unilateral cochlear implantation at the age of 1 year, and 5 year follow-up showed satisfactory speech and language outcomes. Our results further indicate that MYO15A-associated hearing loss is good candidates for cochlear implantation, which is in accordance with previous report. In light of our findings and review of the literatures, 58 splice-site variants in MYO15A are correlated with a severe deafness phenotype, composed of 46 canonical splice-site variants and 12 non-canonical splice-site variants.

Genetic Analysis of the LOXHD1 Gene in Chinese Patients With Non-Syndromic Hearing Loss.

Non-syndromic hearing loss (NSHL) is a common neurosensory disease with an extreme genetic heterogeneity which has been linked to variants in over 120 genes. The LOXHD1 gene (DFNB77), encoding lipoxygenase homology domain 1, is a rare hearing loss gene found in several populations. To evaluate the importance of LOXHD1 variants in Chinese patients with NSHL, we performed genetic analysis on LOXHD1 in 2,901 sporadic Chinese patients to identify the aspect and frequency of LOXHD1 causative variants. Next-generation sequencing using a custom gene panel of HL was conducted on 2,641 unrelated patients and whole-exome sequencing on the remaining 260 patients. A total of 33 likely causative variants were identified in 21 patients, including 20 novel variants and 13 previously reported pathogenic variants. Each of the 20 novel variants was evaluated according to ACMG criteria. These findings showed that causative variants in LOXHD1 were found in about 0.72% (21/2,901) of Chinese NSHL patients. This study is by far the largest number of novel variants identified in this gene expanding the range of pathogenic variants in LOXHD1, and suggests that variants in this gene occur relatively commonly in Chinese NSHL patients. This extensive investigation of LOXHD1 in Chinese NSHL patients proposed six recurrent LOXHD1 variants. These findings may assist in both molecular diagnosis and genetic counseling.

Transcriptome analysis of the early stage ifnlr1-mutant zebrafish indicates the immune response to auditory dysfunction.

BACKGROUND: IFNLR1 has been recently identified to be related to autosomal dominant nonsyndromic sensorineural hearing loss (ADNSHL). It is reported to be expressed in the inner ear of mice and the lateral line of zebrafish. However, it remains unclear how defects in this gene lead to hearing loss. OBJECTIVES: To elucidate the global gene expression changes in zebrafish when the expression of ifnlr1 is downregulated. METHODS: Transcriptome analysis was performed on ifnlr1 morpholino knockdown zebrafish and the control zebrafish using RNA-seq technology. RESULTS: The results show that 262 differentially expressed genes (DEGs) were up-regulated while 146 DEGs were down-regulated in the E4I4-Mo zebrafish larvae compared to the control-Mo. Six pathways were significantly enriched, including steroid biosynthesis pathway, adipocytokine signaling pathway, cytokine-cytokine receptor interaction pathway, p53 signaling pathway, AGE-RAGE signaling pathway in diabetic complications, and terpenoid backbone biosynthesis pathway. Among them, three pathways (steroid biosynthesis pathway, cytokine-cytokine receptor interaction pathway and p53 signaling pathway) are immune-associated. CONCLUSIONS: The transcriptome analysis results contribute to the groundwork for future research on the pathogenesis of IFNLR1-associated hearing loss.

Establishment of human induced pluripotent stem cell line (CPGHi002-A) from a 10-month-old female patient with DDOD syndrome carrying a heterozygous c.1516 C > T mutation in ATP6V1B2.

Dominant deafness-onychodystrophy (DDOD) syndrome is a rare, autosomal dominant inherited disorder with no concrete therapies in human. We previously identified c.1516 C > T (p.Arg506*) in ATP6V1B2 as cause of DDOD syndrome, accounting for all cases of this genetic disorder. The induced pluripotent stem cell (iPSC) line was generated using the non-integrating episomal vector method from peripheral blood mononuclear cells (PBMCs) of a 10-month-old female DDOD patient with heterozygous ATP6V1B2 c.1516 C > T variant. This cell line may serve as a useful model for studying the pathogenic mechanisms and treatment of DDOD syndrome.

Comprehensive assessment of the association between genes on JAK-STAT pathway (IFIH1, TYK2, IL-10) and systemic lupus erythematosus: a meta-analysis.

Previous studies have reported that genes relating to JAK-STAT pathway (IFIH1, TYK2 and IL-10) conferred the susceptibility to SLE. In this study, we performed a meta-analysis (including 43 studies) to evaluate the association between IFIH1 (9288 patients and 24,040 controls), TYK2 (4928 patients and 11,536 controls), IL-10 (3623 patients and 4907 controls) polymorphisms and systemic lupus erythematosus (SLE) in a comprehensive way. We found that IFIH1 rs1990760_T allele was associated with risk of SLE in overall population under three models (allelic: P = 2.56 × 10-11, OR 1.135, 95% CI 1.094-1.179, dominant: P = 1.8 × 10-8, OR 1.203, 95% CI 1.128-1.284, recessive: P = 2.6 × 10-7, OR 1.163, 95% CI 1.098-1.231). A strong association had been observed between TYK2 polymorphism rs2304256_C allele and SLE in Europeans (P = 5.82 × 10-5, OR 1.434, 95% CI 1.203-1.710). When coming to overall population, TYK2 rs2304256_C showed a significant association with SLE under recessive model (P = 8.05 × 10-3, OR 1.314, 95% CI 1.074-1.608). However, the other two SNPs (rs12720270, rs280519) of TYK2 were not significant. The results also indicated an association between IL-10 rs1800896_G allele and SLE in Asians under recessive model (P = 4.65 × 10-3, OR 2.623, 95% CI 1.346-5.115), while, IL-10 rs1800896_G had a trend of association with SLE in European population in dominant model (P = 1.21 × 10-2, OR 1.375, 95% CI 1.072-1.764). In addition, we found IL-10 rs1800896 GG homozygote might be associated with increased susceptibility to SLE (GG vs AA, P = 4.65 × 10-3, OR 1.539, 95% CI 1.142-2.072). We concluded that IFIH1 rs1990760_T and TYK2 rs2304256_C alleles were significantly associated with SLE, and IL-10 rs1800896 GG homozygote might have an enhancement effect on SLE risk.

A regulatory mutant on TRIM26 conferring the risk of nasopharyngeal carcinoma by inducing low immune response.

The major histocompatibility complex (MHC) is most closely associated with nasopharyngeal carcinoma (NPC), but the complexity of its genome structure has proven challenging for the discovery of causal MHC loci or genes. We conducted a targeted MHC sequencing in 40 Cantonese NPC patients followed by a two-stage replication in 1065 NPC cases and 2137 controls of Southern Chinese descendent. Quantitative RT-PCR analysis (qRT-PCR) was used to detect gene expression status in 108 NPC and 43 noncancerous nasopharyngeal (NP) samples. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) were used to assess the transcription factor binding site. We discovered that a novel SNP rs117565607_A at TRIM26 displayed the strongest association (OR = 1.909, Pcombined = 2.750 × 10-19 ). We also observed that TRIM26 was significantly downregulated in NPC tissue samples with genotype AA/AT than TT. Immunohistochemistry (IHC) test also found the TRIM26 protein expression in NPC tissue samples with the genotype AA/AT was lower than TT. According to computational prediction, rs117565607 locus was a binding site for the transcription factor Yin Yang 1 (YY1). We observed that the luciferase activity of YY1 which is binding to the A allele of rs117565607 was suppressed. ChIP data showed that YY1 was binding with T not A allele. Significance analysis of microarray suggested that TRIM26 downregulation was related to low immune response in NPC. We have identified a novel gene TRIM26 and a novel SNP rs117565607_A associated with NPC risk by regulating transcriptional process and established a new functional link between TRIM26 downregulation and low immune response in NPC.

Mutation of IFNLR1, an interferon lambda receptor 1, is associated with autosomal-dominant non-syndromic hearing loss.

Background Hereditary sensorineural hearing loss is a genetically heterogeneous disorder. Objectives This study was designed to explore the genetic etiology of deafness in a large Chinese family with autosomal dominant, nonsyndromic, progressive sensorineural hearing loss (ADNSHL). Methods Whole exome sequencing and linkage analysis were performed to identify pathogenic mutation. Inner ear expression of Ifnlr1 was investigated by immunostaining in mice. ifnlr1 Morpholino knockdown Zebrafish were constructed to explore the deafness mechanism. Results We identified a cosegregating heterozygous missense mutation, c.296G>A (p.Arg99His) in the gene encoding interferon lambda receptor 1 (IFNLR1) - a protein that functions in the Jak/ STAT pathway- are associated with ADNSHL Morpholino knockdown of ifnlr1 leads to a significant decrease in hair cells and non-inflation of the swim bladder in late-stage zebrafish, which can be reversed by injection with normal Zebrafish ifnlr1 mRNA. Knockdown of ifnlr1 in zebrafish causes significant upregulation of cytokine receptor family member b4 (interleukin-10r2), jak1, tyrosine kinase 2, stat3, and stat5b in the Jak1/STAT3 pathway at the mRNA level. ConclusionIFNLR1 function is required in the auditory system and that IFNLR1 mutations are associated with ADNSHL. To the best of our knowledge, this is the first study implicating an interferon lambda receptor in auditory function.

Identification of TMPRSS3 as a Significant Contributor to Autosomal Recessive Hearing Loss in the Chinese Population.

Hereditary hearing loss is characterized by a high degree of genetic heterogeneity. Mutations in the TMPRSS3 (transmembrane protease, serine 3) gene cause prelingual (DFNB10) or postlingual (DFNB8) deafness. In our previous study, three pathogenic mutations in TMPRSS3 were identified in one Chinese family. To evaluate the importance of TMPRSS3 mutations in recessive deafness among the Chinese, we screened 150 autosomal recessive nonsyndromic hearing loss (ARNSHL) families and identified 6 that carried seven causative TMPRSS3 mutations, including five novel mutations (c.809T>A, c.1151T>G, c.1204G>A, c.1244T>C, and c.1250G>A) and two previously reported mutations (c.323-6G>A and c.916G>A). Each of the five novel mutations was classified as severe, by both age of onset and severity of hearing loss. Together with our previous study, six families were found to share one pathogenic mutation (c.916G>A, p.Ala306Thr). To determine whether this mutation arose from a common ancestor, we analyzed six short tandem repeat (STR) markers spanning the TMPRSS3 gene. In four families, we observed linkage disequilibrium between p.Ala306Thr and STR markers. Our results indicate that mutations in TMPRSS3 account for about 4.6% (7/151) of Chinese ARNSHL cases lacking mutations in SLC26A4 or GJB2 and that the recurrent TMPRSS3 mutation p.Ala306Thr is likely to be a founder mutation.

Associations between PTPN22 and TLR9 polymorphisms and systemic lupus erythematosus: a comprehensive meta-analysis.

Previous studies have explored the relationship of PTPN22 and TLR9 polymorphisms with systemic lupus erythematosus (SLE). In consideration of the population stratification, conflicting results and updating data, we conducted a comprehensive meta-analysis, which consists of a total of 17 research articles (9120 cases and 11,724 controls) for PTPN22 and 20 articles (including up to 2808 cases and 3386 controls) for TLR9. Significant association was verified between PTPN22 rs2476601 and SLE in the overall population (OR = 1.511 per T allele, 95% CI 1.338-1.706, P = 2.931 × 10-11) and under dominant model of T allele (TT+CT vs. CC: OR = 1.531, 95% CI 1.346-1.742, P = 9.17 × 10-11). Analysis after stratification by ethnicity indicated that PTPN22 rs2476601 was related to SLE in Americans (OR = 2.566, 95% CI 1.796-3.665, P = 2.219 × 10-7), Europeans (OR = 1.399, 95% CI 1.261-1.552, P = 2.153 × 10-10), and Africans (OR = 4.14, 95% CI 1.753-9.775, P = 1.0 × 10-3). We did not observe any association between TLR9 polymorphisms (rs187084, rs352140, rs5743836 and rs352139) and SLE under any model, after excluding the data that were inconsistent with Hardy-Weinberg equilibrium (HWE). In summary, PTPN22 rs2476601 was significantly interrelated with SLE and contributed to susceptibility and development of SLE in Americans, Europeans and Africans in this analysis, while their relationship needs to be validated in Africans by future research.

Transcription Profiles Reveal Sugar and Hormone Signaling Pathways Mediating Flower Induction in Apple (Malus domestica Borkh.).

Flower induction in apple (Malus domestica Borkh.) is regulated by complex gene networks that involve multiple signal pathways to ensure flower bud formation in the next year, but the molecular determinants of apple flower induction are still unknown. In this research, transcriptomic profiles from differentiating buds allowed us to identify genes potentially involved in signaling pathways that mediate the regulatory mechanisms of flower induction. A hypothetical model for this regulatory mechanism was obtained by analysis of the available transcriptomic data, suggesting that sugar-, hormone- and flowering-related genes, as well as those involved in cell-cycle induction, participated in the apple flower induction process. Sugar levels and metabolism-related gene expression profiles revealed that sucrose is the initiation signal in flower induction. Complex hormone regulatory networks involved in cytokinin (CK), abscisic acid (ABA) and gibberellic acid pathways also induce apple flower formation. CK plays a key role in the regulation of cell formation and differentiation, and in affecting flowering-related gene expression levels during these processes. Meanwhile, ABA levels and ABA-related gene expression levels gradually increased, as did those of sugar metabolism-related genes, in developing buds, indicating that ABA signals regulate apple flower induction by participating in the sugar-mediated flowering pathway. Furthermore, changes in sugar and starch deposition levels in buds can be affected by ABA content and the expression of the genes involved in the ABA signaling pathway. Thus, multiple pathways, which are mainly mediated by crosstalk between sugar and hormone signals, regulate the molecular network involved in bud growth and flower induction in apple trees.

Targeted gene capture and massively parallel sequencing identify TMC1 as the causative gene in a six-generation Chinese family with autosomal dominant hearing loss.

Hereditary nonsyndromic hearing loss is extremely heterogeneous. Mutations in the transmembrane channel-like gene1 (TMC1) are known to cause autosomal dominant and recessive forms of nonsyndromic hearing loss linked to the loci of DFNA36 and DFNB7/11, respectively. We characterized a six-generation Chinese family (5315) with progressive, postlingual autosomal dominant nonsyndromic hearing loss (ADNSHL). By combining targeted capture of 82 known deafness genes, next-generation sequencing and bioinformatic analysis, we identified TMC1 c.1714G>A (p. D572N) as the disease-causing mutation. This mutation co-segregated with hearing loss in other family members and was not detected in 308 normal controls. In order to determine the prevalence of TMC1 c.1714G>A in Chinese ADNSHL families, we used DNA samples from 67 ADNSHL families with sloping audiogram and identified two families carry this mutation. To determine whether it arose from a common ancestor, we analyzed nine STR markers. Our results indicated that TMC1 c.1714G>A (p.D572N) account for about 4.4% (3/68) of ADNSHL in the Chinese population.

Identification of Two Novel Compound Heterozygous PTPRQ Mutations Associated with Autosomal Recessive Hearing Loss in a Chinese Family.

Mutations in PTPRQ are associated with deafness in humans due to defects of stereocilia in hair cells. Using whole exome sequencing, we identified responsible gene of family 1572 with autosomal recessively non-syndromic hearing loss (ARNSHL). We also used DNA from 74 familial patients with ARNSHL and 656 ethnically matched control chromosomes to perform extended variant analysis. We identified two novel compound heterozygous missense mutations, c. 3125 A>G p.D1042G (maternal allele) and c.5981 A>G p.E1994G (paternal allele), in the PTPRQ gene, as the cause of recessively inherited sensorineural hearing loss in family 1572. Both variants co-segregated with hearing loss phenotype in family 1572, but were absent in 74 familial patients. Heterozygosity for c. 3125 A>G was identified in two samples from unaffected Chinese individuals (656 chromosomes). Therefore, the hearing loss in this family was caused by two novel compound heterozygous mutations in PTPRQ.

[Effects of environmental factors at different altitudes on leaves and fruit quality of Fuji apple].

To inquire the different performances of the leaves and fruit quality of Fuji apple tress at various altitudes and their responses to the environmental factors, indices including leaf morphology, anatomy, δ13 C, and fruit quality of the Fuji apple trees at respective altitudes of 1375 m, 1575 m and 1715 m were investigated and their responses to environmental factors were determined following stepwise regression analysis. The results showed that 6 factors like the warmth index, Bailey's index, photosynthetically active radiation (PAR), coldness index, ultraviolet B and the annual precipitation dominantly affected the characteristic parameters of leaves and fruit. Elevation increase was matched by the decreasing warmth index, rising Bailey' s index, intenser PAR, higher coldness index, stronger ultraviolet B and heavier annual precipitation; meanwhile, the leaf structure and fruit quality parameters also displayed evident trends of change accordingly, namely, leaf parameters like leaf thickness, cuticle thickness, ratio of palisade and spongy, maximum conduit diameter, δ13C and nitrogen content per unit area increased gradually, and oppositely, leaf length-width ratio, specific leaf area, stoma length-width ratio and ratio of upper and lower epidermis to the leaf thickness decreased gradually; similarly, fruit parameters such as fruit shape index, fruit hardness, sugar-acid ratio, total color and the a/b-value ascended while the titratable acid and the hue angle descended. With increasing the altitude, the photosynthetic rate and water use efficiency of leaves were enhanced, and the fruit sugar-acid ratio climbed and the fruit flavor and color improved. Therefore, it could be safely concluded that within the altitude range between 1375 and 1715 m, environmental factors at a higher altitude favored Fuji apple growth.

Novel compound heterozygous mutations in MYO7A Associated with Usher syndrome 1 in a Chinese family.

Usher syndrome is an autosomal recessive disease characterized by sensorineural hearing loss, age-dependent retinitis pigmentosa (RP), and occasionally vestibular dysfunction. The most severe form is Usher syndrome type 1 (USH1). Mutations in the MYO7A gene are responsible for USH1 and account for 29-55% of USH1 cases. Here, we characterized a Chinese family (no. 7162) with USH1. Combining the targeted capture of 131 known deafness genes, next-generation sequencing, and bioinformatic analysis, we identified two deleterious compound heterozygous mutations in the MYO7A gene: a reported missense mutation c.73G>A (p.G25R) and a novel nonsense mutation c.462C>A (p.C154X). The two compound variants are absent in 219 ethnicity-matched controls, co-segregates with the USH clinical phenotypes, including hearing loss, vestibular dysfunction, and age-dependent penetrance of progressive RP, in family 7162. Therefore, we concluded that the USH1 in this family was caused by compound heterozygous mutations in MYO7A.

A novel mutation in the TECTA gene in a Chinese family with autosomal dominant nonsyndromic hearing loss.

TECTA-related deafness can be inherited as autosomal-dominant nonsyndromic deafness (designated DFNA) or as the autosomal-recessive version. The α-tectorin protein, which is encoded by the TECTA gene, is one of the major components of the tectorial membrane in the inner ear. Using targeted DNA capture and massively parallel sequencing (MPS), we screened 42 genes known to be responsible for human deafness in a Chinese family (Family 3187) in which common deafness mutations had been ruled out as the cause, and identified a novel mutation, c.257-262CCTTTC>GCT (p. Ser86Cys; p. Pro88del) in exon 3 of the TECTA gene in the proband and his extended family. All affected individuals in this family had moderate down-sloping hearing loss across all frequencies. To our knowledge, this is the second TECTA mutation identified in Chinese population. This study demonstrates that targeted genomic capture, MPS, and barcode technology might broaden the availability of genetic testing for individuals with undiagnosed DFNA.

Novel compound heterozygous mutations in the MYO15A gene in autosomal recessive hearing loss identified by whole-exome sequencing.

BACKGROUND: Inherited genetic defects play an important role in congenital hearing loss, contributing to about 60% of deafness occurring in infants. Hereditary nonsyndromic hearing loss is highly heterogeneous, and most patients with a presumed genetic etiology lack a specific molecular diagnosis. METHODS: By whole exome sequencing, we identified responsible gene of family 4794 with autosomal recessively nonsyndromic hearing loss (ARNSHL). We also used DNA from 56 Chinese familial patients with ARNSHL (autosomal recessive nonsyndromic hearing loss) and 108 ethnicity-matched negative samples to perform extended variants analysis. RESULTS: We identified MYO15A c.IVS25+3G>A and c.8375 T>C (p.V2792A) as the disease-causing mutations. Both mutations co-segregated with hearing loss in family 4794, but were absent in the 56 index patients and 108 ethnicity-matched controls. CONCLUSIONS: Our results demonstrated that the hearing loss of family 4794 was caused by novel compound heterozygous mutations in MYO15A.

Novel compound heterozygous TMC1 mutations associated with autosomal recessive hearing loss in a Chinese family.

Hereditary nonsyndromic hearing loss is highly heterogeneous and most patients with a presumed genetic etiology lack a specific diagnosis. It has been estimated that several hundred genes may be associated with this sensory deficit in humans. Here, we identified compound heterozygous mutations in the TMC1 gene as the cause of recessively inherited sensorineural hearing loss by using whole-exome sequencing in a family with two deaf siblings. Sanger sequencing confirmed that both siblings inherited a missense mutation, c.589G>A p.G197R (maternal allele), and a nonsense mutation, c.1171C>T p.Q391X (paternal allele), in TMC1. We also used DNA from 50 Chinese familial patients with ARNSHL and 208 ethnicity-matched negative samples to perform extended variants analysis. Both variants co-segregated in family 1953, which had the hearing loss phenotype, but were absent in 50 patients and 208 ethnicity-matched controls. Therefore, we concluded that the hearing loss in this family was caused by novel compound heterozygous mutations in TMC1.