Ethnogeographic prevalence and implications of the 677C>T and 1298A>C polymorphisms in US primary care populations.

Variants of the gene have been associated with a wide range of diseases. The present study analyzed data from clinical genotyping of and in 1405 patients in urban primary care settings. Striking differences in ethnogeographic frequencies of polymorphisms were observed. African-Americans appear to be protected from MTHFR deficiency. Hispanics and Caucasians may be at elevated risk due to increased frequencies of and , respectively. Individuals carrying mutations for both genes were rare and doubly homozygous mutants were absent, suggesting the is extremely rare in the greater population. The results suggest multilocus genotyping may yield deeper insight into the ethnogeographic association between variants and disease.