About one child in a thousand in Britain is born deaf. The cause is genetic in about 60% of cases (0.6 per 1000 births) and about 30% of genetic deafness (0.18 per thousand births) is syndromic and 70% (0.42 per 1000 births) non-syndromic (no other clinical features). About 80% of non-syndromic genetic deafness (about a third of all congenital deafness) is thought to be caused by recessive genes. About 33 recessive genes for non-syndromic deafness have been mapped …