A history of polygamy in an area near the Arizona-Utah border has led to a cluster of a rare genetic disease, BBC Future reports.
Theodore Darby, a doctor who specializes in rare childhood diseases, tells the BBC that he became stumped by the case of a little boy with distinct facial features and physical and mental disabilities. A special urine analysis detected a fumarase deficiency, of which there had been about a dozen known cases. However, the boy's sister had the condition, as did eight other children from the same area.
The BBC notes that the region is home to many members of the Fundamentalist Church of Jesus Christ of Latter-Day Saints, some of whom practice polygamy. It adds that between 75 percent and 80 percent of the residents of Short Creek are related to Joseph Jessop and John Barlow, the two men who founded the town.
According to the BBC, the fumarase deficiency gene variant has been traced to Joseph Jessop and his first wife Martha Yeates, who had 14 children, one of whom married into the Barlow family. Thousands of people in the area are now thought to carry the variant.
"With polygyny you're decreasing the overall genetic diversity because a few men are having a disproportionate impact on the next generation," Mark Stoneking from the Max Planck Institute for Evolutionary Anthropology tells the BBC. "Random genetic mutations become more important."