The deleted region hereby reported encompassed 34 known genes, including GJA3, GJB2, and GJB6, which are responsible for autosomal recessive deafness, FGF9, which plays crucial roles in embryonic neurological development, and ATP8A2, which causes a cerebellar ataxia and disequilibrium syndrome.
Mutations in the GJB2 gene are the most common cause of prelingual, non-syndromic autosomal recessive deafness in many populations; the c.35delG mutation is the most common in Caucasian populations.
The single-nucleotide guanine deletion (35delG) of the GJB2 gene coding for connexin 26 was shown to be the main genetic cause of autosomal recessive deafness among Europeans.
Autosomal recessive deafness 1A (DFNB1A) in Yakut population isolate in Eastern Siberia: extensive accumulation of the splice site mutation IVS1+1G>A in GJB2 gene as a result of founder effect.
Mutations in the connexin 26 gene (GJB2) cause a significant proportion of prelingual non-syndromic autosomal recessive deafness in all populations studied so far.
Autosomal recessive deafness has been linked both to the monogenetic occurrence of mutated GJB2 or the GJB6 deletion del(GJB6-D13S1830) and digenic GJB2/del(GJB6-D13S1830) inheritance.
Mutations in the Connexin-26 gene have been shown to be a major contributor to prelingual, nonsyndromic, autosomal recessive deafness in many populations.
Though mutations in the GJB2 gene have been shown to cause autosomal recessive deafness in Indian families, the frequencies of the various mutations are still unknown.
Mutations in the gene encoding the gap-junction protein connexin 26 (GJB2) on chromosome 13q11 (DFNB1 locus) have been shown as a major contributor to prelingual, non-syndromic, autosomal recessive deafness in Caucasian populations.
The GJB2 (connexin 26) gene, one of the major genes responsible for autosomal recessive deafness, has been investigated previously by a variety of techniques, including PCR-SSCP and sequencing of the entire gene for screening of unknown mutations, and allele-specific PCR, ASO, and PCR-mediated site-directed mutagenesis for the detection of the common mutation 35delG.
These findings are in agreement with a recent study showing that mutations in the connexin26 gene are associated with genetic forms of deafness in three Pakistani families and that GJB2 is DFNB1.