INTRODUCTION The contribution of Gap junction beta-2 protein (GJB2) to the genetic load of deafness and its mutation spectra vary among different ethnic groups. OBJECTIVE In this study, the mutation spectrum and audiologic features of patients with GJB2 mutations were evaluated with a specific focus on residual hearing. METHODS An initial cohort of 588 subjects from 304 families with varyin...

Mutations in the COCH (coagulation factor C homology) gene have been attributed to DFNA9 (deafness, autosomal-dominant 9), an autosomal-dominant non-syndromic hearing loss disorder. However, the mechanisms responsible for DFNA9 hearing loss remain unknown. Here, we demonstrate that mutant cochlin, the protein product of the COCH gene, forms a stable dimer that is sensitive to reducing agent. In...

The association of congenital corneal dystrophy with teenage onset perceptive hearing loss (Harboyan syndrome) has been reported in two sibships, one with consanguineous parents, which were consistent with autosomal recessive transmission. We have observed a Moroccan sibship where four girls and one boy were affected with this rare syndrome. The parents were first cousins once removed and unaff...

In 20% of cases, hereditary non-syndromic hearing loss has an autosomal dominant inheritance (ADNSHL). To date, more than 50 loci for ADNSHL have been mapped to different chromosomal regions. In order to verify whether genomic alterations contribute to the hearing loss etiology and to search for novel deafness candidate loci, we investigated probands from families with ADNSHL by oligonucleotide...

Autosomal recessive non-syndromic hearing loss (ARNSHL) is defined as a genetically heterogeneous disorder. The aim of the present study was to screen for pathogenic variants in an Iranian pedigree with ARNSHL. Next-generation targeted sequencing of 127 deafness genes in the proband detected two novel variants, a homozygous missense variant in PTPRQ (c.2599 T>C, p.Ser867Pro and a heterozygous m...

Mutations in the autosomal genes TMPRSS3, TMC1, USHIC, CDH23 and TMIE are known to cause hereditary hearing loss. To study the contribution of these genes to autosomal recessive, non-syndromic hearing loss (ARNSHL) in India, we examined 374 families with the disorder to identify potential mutations. We found four mutations in TMPRSS3, eight in TMC1, ten in USHIC, eight in CDH23 and three in TMI...

The most common syndromic form of hereditary SNHL, Pendred syndrome (PS) was described by Pendred in 1896. The condition is autosomal recessive, and affected individuals also have goiter. The prevalence of PS is estimated at 7.5 to 10 per 100,000 individuals, suggesting that the syndrome may account for 10% of hereditary deafness. The hearing loss is usually congenital and severe to profound, a...

The mouse shaker-1 locus, Myo7a, encodes myosin VIIA and mutations in the orthologous gene in humans cause Usher syndrome type 1B or non-syndromic deafness. Myo7a is expressed very early in sensory hair cell development in the inner ear. We describe the effects of three mutations on cochlear hair cell development and function. In the Myo7a816SB and Myo7a6J mutants, stereocilia grow and form row...

In mammalian development, the ear arises from a co-alescence of ectoderm, mesoderm, endoderm, and neu-ral crest–derived cells. Initially, an ectodermal placode invaginates to form a pouch of cells called the otocyst. The otocyst resides between the first and second bra-chial arches of the embryo. Paraxial mesoderm and neu-Boston, Massachusetts 02115 ral crest that underlie the epithelial coveri...