Previous molecular etiological studies have demonstrated that the most common molecular changes in Chinese patients with nonsyndromic hearing loss (NSHL) involved gap junction protein β 2, solute carrier family 26, member 4 (SLC26A4), and mitochondrial DNA 12S rRNA.
Low frequency of GJB2 mutations in this population is probably indicative of the fact that other genes may be involved in nonsyndromic hearing loss in Ilam populations.
The c.235delC mutation showed a particularly wide spectrum of hearing loss, from mild to profound and significantly better hearing thresholds at 250 Hz and 2k Hz than in the non-p.V37I and non-235delC nonsyndromic hearing loss and deafness 1(DFNB1) subjects.
In this study, we investigated the genetic etiology of nonsyndromic deafness in four consanguineous and two multiplex Uyghur families in which mutations in common deafness genes GJB2, SLC26A4 and MT-RNR1 were excluded.
This study aimed to investigate the mutations of GJB2, mitochondrial DNA 12S rRNA1555A>G, and SLC26A4 genes in Han Chinese, Hui people, and Tibetan ethnicities in patients with nonsyndromic hearing loss (NSHL) in northwest China.
We recruited 70 participants with nonsyndromic deafness segregating as an apparently recessive trait and directly sequenced the GJB2 coding region from their DNA.
Mutations in the human gene encoding connexin 26 (Cx26 or GJB2) cause either nonsyndromic deafness or syndromic deafness associated with skin diseases.
Our recent studies indicate that nonsyndromic hearing loss (NSHL) in the Saudi Arabian population is genetically heterogeneous and is not caused by mutations in GJB2 and GJB6, the most common genes for deafness in various populations worldwide.
In idiopathic familial cases of NSHI lacking known pathogenic alterations in GJB2, we identified a T→C transition (refSNP: rs117685390) in a putative transcription factor binding sequence 228 bp proximal to the transcriptional start site at a homozygous frequency of 0.125 (n = 40), significantly overrepresented in comparison to the homozygous allele frequencies of 0.043 in the normal-hearing Caucasian population (n = 211; p < 0.001).
We screened 160 unrelated Japanese with severe to profound recessive nonsyndromic hearing loss (ARNSHL) without GJB2 or SLC26A4 mutations, and 192 controls with normal hearing.
Therefore, to define the importance of other genes in contributing to an ARNSHL phenotype in the Iranian population, we used homozygosity mapping to identify regions of autozygosity-by-descent in 144 families which two or more progeny had ARNSHL but were negative forGJB2 gene mutations.
Congenital CMV infection accounts for approximately 20% of all cases of neonatal hearing loss, while the GJB2 mutation accounts for 30-50% of all cases of profound nonsyndromic hearing loss.