Screening mutations of OTOF gene in Chinese patients with auditory neuropathy, including a familial case of temperature-sensitive auditory neuropathy

International audienceBackgroundMutations in OTOF gene, encoding otoferlin, cause DFNB9 deafness and non-syndromic auditory neuropathy (AN). The aim of this study is to identify OTOF mutations in Chinese patients with non-syndromic auditory neuropathy.Methods73 unrelated Chinese Han patients with AN, including one case of temperature sensitive non-syndromic auditory neuropathy (TS-NSRAN) and 92 ethnicity-matched controls with normal hearing were screened. Forty-five pairs of PCR primers were designed to amplify all of the exons and their flanking regions of the OTOF gene. The PCR products were sequenced and analyzed for mutation identification.ResultsFive novel possibly pathogenic variants (c.1740delC, c.2975_2978delAG, c.1194T>A, c.1780G>A, c.4819C > T) were identified in the group of 73 AN patients, in which two novel mutant alleles (c.2975_2978delAG + c.4819C > T) were identified in one Chinese TS-NSRAN case. Besides, 10 non-pathogenic variants of the OTOF gene were found in AN patients and controls.ConclusionsScreening revealed that mutations in the OTOF gene account for AN in 4 of 73(5.5%) sporadic AN patients, which shows a lower genetic load of that gene in contrast to the previous studies based on other populations. Notably, we found two novel mutant alleles related to temperature sensitive non-syndromic auditory neuropathy. This mutation screening study further confirms that the OTOF gene contributes to ANs and to TS-NSRAN

Variants of OTOF and PJVK Genes in Chinese Patients with Auditory Neuropathy Spectrum Disorder

BACKGROUND: Mutations in OTOF and PJVK genes cause DFNB9 and DFNB59 types of hearing loss, respectively. The patients carrying pathogenic mutations in either of these genes may show the typical phenotype of auditory neuropathy spectrum disorder (ANSD). The aim of the present study was to identify OTOF and PJVK mutations in sporadic ANSD patients. METHODS AND FINDINGS: A total of 76 unrelated Chinese non-syndromic ANSD patients were sequenced on the gene OTOF and PJVK exon by exon. Variants were valued in 105 controls with normal hearing to verify the carrying rate. We identified one pathogenic mutation (c.1194T>A) and three novel, possibly pathogenic, variants (c.3570+2T>C, c.4023+1 G>A, and c.1102G>A) in the OTOF gene, and one novel, possibly pathogenic, variant (c.548G>A) in PJVK. Moreover, we found three novel missense mutations within the exons of OTOF. CONCLUSIONS: As we identified 4 and 1 possible pathogenic variants of the OTOF gene and the PJVK gene, respectively, we believe that screening in these genes are important in sporadic ANSD patients. The pathogenicity of these novel mutations needs further study because of their single heterozygous nature. Knowledge on the mutation spectra of these genes in Chinese would be beneficial in understanding the genetic character of this worldwide disease

Newborn Genetic Screening for Hearing Impairment: A Preliminary Study at a Tertiary Center

Universal newborn hearing screening (UNHS) is of paramount importance for early identification and management of hearing impairment in children. However, infants with slight/mild, progressive, or late-onset hearing impairment might be missed in conventional UNHS. To investigate whether genetic screening for common deafness-associated mutations could assist in identifying these infants, 1017 consecutive newborns in a tertiary hospital were subjected to both newborn hearing screening using a two-step distortion-product otoacoustic emissions (DPOAE) screening and newborn genetic screening (NGS) for deafness. The NGS targeted 4 deafness-associated mutations commonly found in the Taiwanese population, including p.V37I (c.109G>A) and c.235delC of the GJB2 gene, c.919-2A>G of the SLC26A4 gene, and mitochondrial m.1555A>G of the 12S rRNA gene. The results of the NGS were then correlated to the results of the NHS. Of the 1017 newborns, 16 (1.6%) had unilateral DPOAE screening failure, and 22 (2.2%) had bilateral DPOAE screening failure. A total of 199 (19.6%) babies were found to have at least 1 mutated allele on the NGS for deafness, 11 (1.1%) of whom were homozygous for GJB2 p.V37I, 6 (0.6%) compound heterozygous for GJB2 p.V37I and c.235delC, and 1 (0.1%) homoplasmic for m.1555A>G, who may potentially have hearing loss. Among them, 3 babies, 5 babies, and 1 baby, respectively, passed the NHS at birth. Comprehensive audiological assessments in the 9 babies at 3 months identified 1 with slight hearing loss and 2 with mild hearing loss. NGS for common deafness-associated mutations may identify infants with slight/mild or potentially progressive hearing impairment, thus compensating for the inherent limitations of the conventional UNHS

Identification of five novel BOR mutations in human EYA1 gene associated with branchio-oto-renal syndrome by a DHPLC-based assay

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Identification of five novel BOR mutations in human EYA1 gene associated with branchio-oto-renal syndrome by a DHPLC-based assay

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Mapping of a new autosomal dominant non-syndromic hearing loss locus (DFNA43) to chromosome 2p12

Hearing impairment (HI) is the most frequent sensory defect with wide genetic heterogeneity. Approximately 80% of genetic hearing loss is non-syndromic and 15-25% of exhibit autosomal dominant inheritance. We analysed an Italian three generation family in which non-syndromic hearing impairment is transmitted as an autosomal dominant trait. Onset of HI in all affected subjects occurred in the second decade of life, with subsequent gradual progression from moderate to profound loss. HI was bilateral and symmetrical, involving all frequencies. After exclusion of the known DFNA loci with markers from the Hereditary Hearing Loss Homepage (URL: http://dnalabwww.uia.ac.be/dnalab/hhh), a genome wide scan was carried out using 358 highly informative microsatellite markers. Significant linkage (Zmax=4.21, theta=0) was obtained with chromosome 2p12 markers. The results were confirmed by multipoint analysis (Zmax=4.51), using the location score method. Haplotype analysis defined a 9.6 cM disease gene interval on chromosome 2 without overlap with the other identified loci. Fine mapping and identification of candidate genes are in progress

Mapping of a new autosomal dominant non-syndromic hearing loss locus (DFNA43)t chromosome 2p12.

Hearing impairment (HI) is the most frequent sensory defect with wide genetic heterogeneity. Approximately 80% of genetic hearing loss is non-syndromic and 15-25% of exhibit autosomal dominant inheritance. We analysed an Italian three generation family in which non-syndromic hearing impairment is transmitted as an autosomal dominant trait. Onset of HI in all affected subjects occurred in the second decade of life, with subsequent gradual progression from moderate to profound loss. HI was bilateral and symmetrical, involving all frequencies. After exclusion of the known DFNA loci with markers from the Hereditary Hearing Loss Homepage (URL: http://dnalab-www.uia.ac.be/dnalab/hhh), a genome wide scan was carried out using 358 highly informative microsatellite markers. Significant linkage (Zmax=4.21, theta=0) was obtained with chromosome 2p12 markers. The results were confirmed by multipoint analysis (Zmax=4.51), using the location score method. Haplotype analysis defined a 9.6 cM disease gene interval on chromosome 2 without overlap with the other identified loci. Fine mapping and identification of candidate genes are in progress

Mapping of a new autosomal dominant non-syndromic hearing loss locus (DFNA43) to chromosome 2p12

Hearing impairment (HI) is the most frequent sensory defect with wide genetic heterogeneity. Approximately 80% of genetic hearing loss is non-syndromic and 15-25% of exhibit autosomal dominant inheritance. We analysed an Italian three generation family in which non-syndromic hearing impairment is transmitted as an autosomal dominant trait. Onset of HI in all affected subjects occurred in the second decade of life, with subsequent gradual progression from moderate to profound loss. HI was bilateral and symmetrical, involving all frequencies. After exclusion of the known DFNA loci with markers from the Hereditary Hearing Loss Homepage (URL: http://dnalabwww.uia.ac.be/dnalab/hhh), a genome wide scan was carried out using 358 highly informative microsatellite markers. Significant linkage (Zmax=4.21, theta=0) was obtained with chromosome 2p12 markers. The results were confirmed by multipoint analysis (Zmax=4.51), using the location score method. Haplotype analysis defined a 9.6 cM disease gene interval on chromosome 2 without overlap with the other identified loci. Fine mapping and identification of candidate genes are in progress