BACKGROUND Hereditary forms of hearing loss are classified as syndromic, when deafness is associated with other clinical features, or non-syndromic, when deafness occurs without other clinical features. Many types of syndromic deafness have been described, some of which have been mapped to specific chromosomal regions. METHODS Here we describe a family with progressive sensorineural hearing l...

BACKGROUND The estimated prevalence of Sensory Neural Hearing Loss (SNHL) in patients less than 18 years of age is 6 per 1000. Roughly 50% of cases of congenital SNHL can be linked to a genetic cause, with approximately 30% being syndromic and the remaining 70% being non-syndromic. The term "syndromic" implies the presence of other distinctive clinical features in addition to hearing loss. The ...

It has long been recognized that heredity plays a major role in hearing impairment. Although the facts about the genetic basis of hearing loss have fascinated both clinicians and geneticists for a long time, it is only within the last few years that the genes and molecular mechanisms underlying deafness have begun to be discovered. There is a great deal of genetic heterogeneity in deafness. Thi...

Nonsyndromic deafness is genetically heterogeneous but phenotypically similar among many cases. Though a variety of targeted next-generation sequencing (NGS) panels has been recently developed to facilitate genetic screening of nonsyndromic deafness, some syndromic deafness genes outside the panels may lead to clinical phenotypes similar to nonsyndromic deafness. In this study, we performed com...

Genetic research into the causes of deafness has advanced considerably in the last years. Progress has been made in both discovering loci and cloning genes associated with syndromic and non-syndromic hearing loss. To date, close to 75 loci have been identified and 29 genes have been cloned for non-syndromic deafness. The proteins these genes encode range from transcription factors to molecular ...

BACKGROUND Although over 60 non-syndromic deafness genes have been identified to date, the etiologic contribution of most deafness genes remained elusive. In this study, we addressed this issue by targeted next-generation sequencing of a large cohort of non-syndromic deaf probands. METHODS Probands with mutations in commonly screened deafness genes GJB2, SLC26A4 and MT-RNR1 were pre-excluded ...

The GJB2 gene is located on chromosome 13q12 and it encodes the connexin 26, a transmembrane protein involved in cell-cell attachment of almost all tissues. GJB2 mutations cause autosomal recessive (DFNB1) and sometimes dominant (DFNA3) non-syndromic sensorineural hearing loss. Moreover, it has been demonstrated that connexins are involved in regulation of growth and differentiation of epidermi...

Hereditary deafness has proved to be extremely heterogeneous genetically with more than 40 genes mapped or cloned for non-syndromic dominant deafness and 30 for autosomal recessive non-syndromic deafness. In spite of significant advances in the understanding of the molecular basis of hearing loss, identifying the precise genetic cause in an individual remains difficult. Consequently, it is impo...

Autosomal recessive childhood-onset non-syndromic deafness is one of the most frequent forms of inherited hearing impairment. Recently five different chromosomal regions, 7q31, 11q13.5, 13q12, 14q and the pericentromeric region of chromosome 17, have been shown to harbour disease loci for this type of neurosensory deafness. We have studied a large family from Pakistan, containing several consan...

Mitochondrion harbors its own DNA, known as mtDNA, encoding certain essential components of the mitochondrial respiratory chain and protein synthesis apparatus. mtDNA mutations have an impact on cellular ATP production and many of them are undoubtedly a factor that contributes to sensorineural deafness, including both syndromic and non-syndromic forms. Hot spot regions for deafness mutations ar...