We have also analyzed by means of AMOVA the interaction between APOAV and a marker of the apo C-III gene (APOCIII) with a significant TG-increasing effect in FCHL patients (C1100T; exon 3) (9) and detected a significant interaction (P = 0.
It is difficult to speculate about the mechanism by which apo AV contributes to FCHL because very little is known about the protein encoded by APOAV.
At present we report that the polymorphic marker SNP3 of APOAV is overrepresented in FCHL and can be considered as a predisposing factor for this condition.
None of their families met the criteria to be classified as FCHL.
Those members of FCHL families with a hyperlipidemic phenotype (n = 30) and the group of healthy control subjects (n = 56) were comparable with respect to age, BMI, and male/female proportion (Table 1).
Concentrations of cholesterol and triglycerides in plasma, VLDL, IDL, and LDL as well as plasma apos B, C-II, and C-III were greater in the FCHL group than in the control subjects.
Plasma retinol concentrations were significantly lower in FCHL individuals (1.
Conversely, in the FCHL group, plasma retinol was positively and significantly correlated with HDL cholesterol (r = 0.
The hypothesis that vitamin A could be involved in the expression of FCHL was based on observations indicating that the increased synthesis of VLDL, which is characteristic of FCHL patients, is reversed by the action of fibrate therapy [20,21].
Our results indicating that plasma retinol concentrations were significantly lower in FCHL than in control subjects are intriguing, in that several phenomena associated with FCHL will now need to be explored.
Firstly, dietary intake of vitamin A could account for the 50% decrease in the circulating concentrations of retinol observed in FCHL subjects compared with controls [22, 23].
In the present study, vitamin A values in the FCHL subjects were not in the range that could be considered as a state of vitamin A deficiency (none of the subjects had plasma vitamin A concentrations below the mean - 2 SD of the control values) and, therefore, the extent to which the observed reductions could affect the intracellular availability of retinoic acid needs to be investigated--particularly in light of evidence indicating that vitamin A regulates the expression of apo A-I and C-III genes in a tissue-specific manner in rats .