Are Deafness Genes Spreading?
Deafness may be becoming more common, according to a study presented here on 6 October at a meeting of the American Society of Human Genetics. The researchers believe increased opportunities for deaf people to meet and marry each other may lead to a rise in frequency of an important class of deafness causing mutations. Gene mutations at more than 200 locations on the genome cause inherited deafness, which accounts for about half of deafness in general. Recently, clinical geneticists reported that faulty copies of a gene called Cx 26 cause about 35% of all cases of deafness. That number seemed remarkably high to Walter Nance, a geneticist at Virginia Commonwealth University in Richmond. From a statistical analysis of data on 19th-century American families with deaf children, he estimated that in those days, Cx 26 mutations accounted for only 17% of inherited deafness. Nance reasoned that intermarriage might explain the increase in Cx 26 deafness, because two parents with …
