Abstract
Background and Objectives: Hearing loss (HL) is the most common sensory deficit in humans. In more than 80% of these cases, the mode of transmission is autosomal recessive. To date 85 loci have been mapped for nonsyndromic deafness with different inheritance patterns. DFNB1 is a locus that contains Connexin26 gene (Cx26 or GJB2). Mutations in Cx26 are responsible for 50% autosomal recessive, non-syndromic hearing loss (ARNSHL) in Caucasians. Around 90 different GJB2 mutations have so far been reported to be associated with recessive, non-syndromic hearing loss.
Materials and Methods: We assess the contribution of Cx26 gene in ARNSHL in 100 probands from the East Azerbaijan Providence. The first phase was screening for 35delG mutations. Heterozygous or negative patients to this mutation (85 patient), were tested for other associated mutations in the coding region of Cx26 gene by applying Single (Strand Conformation Polymorphism/Heteroduplex Analysis, SSCP/HA); a technique with high sensitivity, simplicity and versatility. DNA was extracted from the peripheral blood.
Results: We detected at least 14 different SSCP patterns in 62 chromosomes (36%) of 170 affected chromosomes. Homozygote pattern was detected in 2 chromosomes and in 60 chromosomes had heterozygote pattern. 67% of patients were born in consanguineous families.
Conclusion: Different SSCP patterns were detected in 36% of patients in coding second exon of Cx26 gene. This proves the value of such studying in this disorder in the Azarbaijan Providence.