Mutation analysis of the CX26 gene in sporadic cases with moderate to profound deafness

Non-syndromic neurosensory recessive deafness (NSRD) is one of the most com mon human sensory disorders. Mutations in the connexin 26 gene have been es tablished as a major cause of inherited and sporadic nonsyndromic deafness in different populations. The CX26 gene encodes the gap junction protein connexin 26 (beta-2 GJB2), w hose expression was shown in several tissues and in the cochlea. The 30delG mutation is the most frequent mutation in the CX26 gene. it represents a d eletion of guanosine (G) in a sequence of six Gs extending from position 30 to 35 of the CX26 cDNA. The deletion creates a frameshift resulting in a p remature stop codon and a nan-functional intracellular domain in the protei n. The 30delG mutation can be detected at the molecular level using PCR fol lowed by BsiY/digestion. We screened 164 mainly German patients with non-syndromic sporadic deafness for this mutation to determine its distribution in the German population. The frequency of the mutation in our analyzed patients was lower than in ot her studies and therefore indicates its dependency on geographically distin ct populations.