Science / Medicine : Study Links Gene to Hereditary Deafness

Studies of deafness in 500 descendants of an 18th-Century Costa Rican landowner point for the first time to a gene that might explain many inherited forms of hearing loss. California and Costa Rica researchers reported last week at the International Congress of Human Genetics in Washington, D.C., that this was the first discovery of a gene known to cause primary inherited deafness--that is, deafness that does not result from another hereditary problem.

Pedro E. Leon of the University of Costa Rica and Mary-Claire King of UC Berkeley said they had “mapped” the gene to a small region on chromosome 5, one of the 23 paired chromosomes that carry human genes. The next step will be to isolate the gene and determine precisely how it is causing hearing loss, Leon said.

Kathleen Arnos, a geneticist at Gallaudet University in Washington, said the gene could help explain the cause of many forms of deafness. About one in 1,000 Americans is born deaf, Arnos said. About half of those cases have genetic causes, she said. The rest are caused by such things as viral infections and premature birth.

The researchers studied 53 families, all of whom could be traced to a single ancestor, an 18th-Century landowner named Felix Monge, who suffered from the disorder.