Who Would Have Guessed?

A fundamentalist breakaway Mormon sect in Colorado City, AZ, is being overtaken by a rare birth-defect brought on by inbreeding. The cult's leader arranges all marriages between community members, who are descended from two founding families. The cult's members view the severe disabilities brought on by the inbreeding as a test from God, and those who question this are excommunicated and thrown out of the community.
By the late 1990s, Tarby and his team had discovered fumarase deficiency was occurring in the greatest concentration in the world among the fundamentalist Mormon polygamists of northern Arizona and southern Utah.
Of even greater concern was the fact that the recessive gene that triggers the disease was rapidly spreading to thousands of individuals living in the community because of decades of inbreeding...
Doctors and family members interviewed by New Times say up to 20 children from families in the polygamist community are currently afflicted with the condition that requires full-time attention from caregivers. Victims suffer a range of symptoms, including severe epileptic seizures, inability to walk or even sit upright, severe speech impediments, failure to grow at a normal rate, and tragic physical deformities.