LOW PLASMA VITAMIN-A CONCENTRATIONS IN FAMILIAL COMBINED HYPERLIPIDEMIA

As many as 20% of the survivors of acute myocardial infarction present with the heritable form of hyperlipidemia, termed familial combined h yperlipidemia (FCHL). Some of the genes reported to be involved in thi s disorder, such as those for lipoprotein lipase (LPL) and apolipoprot ein (ape) C-III, are controlled by a peroxisome proliferator-activated receptor (PPAR)/retinoic acid receptor X (RXR) regulatory system, whi ch is retinoic acid dependent. If, as we hypothesized, the availabilit y of retinoic acid or its precursor retinol (vitamin A) could be alter ed in FCHL, this could help explain some aspects of the phenotypic exp ression of the disease. We therefore measured plasma retinol concentra tions in 30 FCHL subjects and 56 controls. Plasma retinol concentratio ns in FCHL subjects were significantly lower than that of control subj ects (1.96 +/- 0.83 mu mol/L vs 2.91 +/- 1.23 mu mol/L, respectively; P <0.0001). This novel finding of significantly decreased concentratio ns of plasma retinol in FCHL relative to control subjects gives suppor t to the hypothesis that vitamin A might be involved in the expression of this disorder.