A new study, led by researchers with the Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, has identified a gene mutation that they estimate dates back to 11,600 B.C., making it the second oldest human disease mutation yet discovered. They estimate that the mutation arose in the Middle East some 13,600 years ago, and is described in people of Arabic, Turkish and Jewish ancestry. It causes a rare, inherited vitamin B12 deficiency called Imerslund-Gräsbeck Syndrome (IGS).
It originated in a single, prehistoric individual and was passed down to that individual’s descendants. This is unusual because such “founder mutations” usually are restricted to specific ethnic groups or relatively isolated populations.
Because the mutation was found in such diverse populations, the researchers were unsure whether it was a true founder mutation that first arose in one individual and was passed down, or whether it was simply a mutation that recurred frequently over time in different populations. Analysis of the gene sequences on either side of the mutation (the haplotype in both the Muslim and Jewish families), pointed to a single mutational event rather than repeated events.
Principal investigator Stephan M. Tanner says, “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.” This mutation accounts for more than half of the cases in the aforementioned populations and for about 15 percent of cases worldwide.