Connexin-26 gene analysis in hearing-impaired newborns

The efficacy and utility of the Connexin-26 (Cx-26) gene (also called GJB2) analysis from DNA isolated from Guthrie newborn screening cards is demonst rated. This analysis precisely defined a major cause of prelingual nonsyndr omic deafness in those children requiring amplification in our study. Guthr ie cards were obtained from 49 deaf children requiring amplification identi fied over the last 5 years by the Rhode Island Newborn Screening Program. C hildren with syndromes or other recognizable causes of hearing loss were ex cluded. DNA was extracted from the Guthrie cards and analyzed sequentially for the Cx-26 35delG mutation and then for the 167delT mutation followed by gene sequencing on remaining heterozygotes. Three of 42 children were 35de lG homozygotes; 2/42 children were 35delG/167delT compound heterozygotes. O ne child was identified as being a 35delG heterozygote with no other mutati on found by sequencing. Nine Guthrie cards yielded no amplification or unin terpretable results. Cx-26 mutations were identified as causing 11.9% of th e deafness in the children studied. In conclusion, Cx-26 analysis is an imp ortant test that identifies a major cause of prelingual nonsyndromic deafne ss. Molecular analysis of hearing-impaired newborns will be important for g enetic counseling in these families. Failures with Guthrie cards may make u se of other collection methods preferable.