Ancient disease mutation identified

U.S. researchers say they've identified the second-oldest human disease mutation yet discovered, dating back to 11,600 B.C. Researchers at Ohio State University estimate the mutation, which causes a rare, inherited vitamin B12 deficiency called Imerslund-Grasbeck syndrome, arose in the Middle East some 13,600 years ago. Only a mutation seen in cystic fibrosis that arose between 11,000 and 52,000 years ago is believed to be older, a university release said Thursday. The mutation is found mostly in people of Arabic, Turkish and Jewish ancestry, researchers said. "Our findings permit reliable genetic diagnostics in suspected cases of IGS in that this mutation should be considered first when genetically screening patients from these populations," OSU researcher Stephan M. Tanner said. Although the mutation is found in different ethnic populations, it originated in a single, prehistoric individual and was passed down to that individual's descendants, researchers said. This is unusual, they said, because such "founder mutations" usually are restricted to specific ethnic groups or relatively isolated populations.