Mutations in the connexin 26 (Cx26) gene (GJB2) are associated with autosomal nonsyndromic hearing loss (ANSHL). This gene is encoding the gap junction protein connexin 26. A frequent point mutation, inherited in autosomal recessive mode, has been identified involving the deletion of a G within a stretch of six Gs at position 30-35 of the GJB2 cDNA. This mutation is the most frequent alteration in European populations. In addition to 35dG, different nucleotide deletions and point mutations were also found in GJB2 gene among nonsyndomic hearing loss individuals.

To date, 28 individuals from 14 affected families in Republic of Macedonia have been analyzed. NciYI digestion of 130 bp fragment form exon 2 of GJB2 gene was used for direct detection od 35delG mutation. The presence of other point mutation or nucleotide deletion in exon 2 of the GJB2 gene was analyzed by single strand polymorphism analysis. We have identified homozygosity for 35delG in five unrelated patients, of whom three were Macedonian and one each of Albanian and Turkish origin, confirming that this mutation is the most prevalent one in Mediterranean countries. In addition we have determined W24X homozygosity in two unrelated patients from Gypsy origin. The prevalence of this mutation was most frequent in India and Pakistan.

These are the first results on molecular basis of deafness in Republic of Macedonia. Also they contribute for determination of an effective and reliable method for detection of the mutations in connexin 26 and for wide screening of carriers.

These results contribute to population genetic and analysis of the genetic pool in Republic of Macedonia.