Strong association of a single nucleotide substitution in the 3'-untranslated region of the apolipoprotein-CIII gene with common hypertriglyceridemia in Arabs.

A potential genetic marker for hypertriglyceridemia and coronary disease, an apolipoprotein-CIII gene allele displaying a single nucleotide substitution, was found in 71% of Arabs with primary hypertriglyceridemia. Over 96% of the unrelated adults possessing this allele showed hypertriglyceridemia. The same allele was found rarely among normotriglyceridemic subjects. In further support of involvement in hypertriglyceridemia, this allele was co-inherited with increased serum triglycerides in a three-generation family. Moreover, a gene dosage effect was also found. A mechanism of action for the allele is suggested by the findings that the subjects possessing the allele show markedly increased very-low-density lipoproteins, decreased high-density lipoproteins, and borderline chylomicronemia demonstrable by lipoprotein electrophoresis. Electrophoresis of the selectively amplified-restricted apolipoprotein-CIII DNA on agarose gel provides a rapid diagnostic test that allows identification of the subjects with this allele in less than a day.