Q ( B-08 ) ¨ The deficit of enzymes of the TCA cycle is rare, indicating the importance of this pathway for survival. Several cases, however, are on record in which there is a severe deficiency of the enzyme that catalyzes the interconversion between fumarate and malate. The patient is characterized by severe neurological impairment, encephalomyopathy, and dystonia developing soon after birth. Urine contains abnormal amounts of fumarate and other metabolites of Krebs Cycle. Which of the above enzymes would be deficient?
A ( B-08 ): (d) fumarase (aka fumarate hydratase deficiency)
The twin border communities of Hildale, Utah, and Colorado City, Arizona, have the highest prevalence of known fumarase deficiency cases. And around half the world population of known fumarase deficiency patients have been found in Arizona (Birth Defect is plaguing children in FLDS towns)
Colorado City, Arizona:
Because of the existence of two closed communities in this area, founded by fundamental polygamist whose families are very inbreeded. In fact, it should be noted that it was not the polygamy which produces this high prevalence of the fumarase deficiency, as could be understood from some press reports, but the fact that this polygamy occurred in a closed population and with a high endogamic behavior. Apparently the founders had a recessive gen for the fumarate deficiency and the marriage among relatives of these two families, or among relatives in the same family, produced the high prevalence of this genetic disease.
For more information about the history of these communities and the prevalence of fumarase deficiency in them, follow these links:
More information about Fumarase deficiency:
Kerrigan, J.F. et al: Fumaric aciduria: clinical and imaging features.