<unk>  is extremely rare - until around 1990 there had only been 13 diagnosed and identified cases worldwide. A cluster of 20 cases has since been documented in the twin towns of Colorado City, Arizona and Hildale, Utah among an inbred community of 10,000 members of the Fundamentalist Church of Jesus Christ of Latter Day Saints. Nicknamed "Polygamist's Down's", the syndrome has been blamed on cousin marriage, but in a larger sense is related to the reproductive isolation of a community among whom 85% are blood relatives of John Y. Barlow or Joseph Smith Jessop.
Fumarase deficiency
Enolase deficiency
Dihydropyrimidine dehydrogenase deficiency
Glutaminase deficiency
Phosphofructokinase deficiency
Hexokinase deficiency
Aldolase A deficiency
Transaldolase deficiency