[Detection of the Arg 3500-->Gln mutation of B apolipoprotein. Value in clinical practice]

Familial defective apolipoprotein B-100, caused by a mutation in position 3500 of apolipoprotein B, induces hypercholesterolaemia, a major risk factor of coronary artery disease. The objective is to evaluate the interest of the detecting subjects bearing the Arg3500-->Gln mutation and to observe the response of these subjects to different physiological and therapeutic situations, in clinical practice.

We performed a systematic screening among hypercholesterolaemic outpatients attending a lipid clinic. The heterozygote subjects were followed up during more than one year and, in some of them, we compared the efficiency of cholesterol-lowering drugs belonging to the different classes: fibrate and statine.

Two probands and 3 related subjects were detected. Three patients were treated. For two patients, reduction of LDL-cholesterol plasma levels was observed with both drugs but was significantly higher with statine than with fibrate. For the third one, carrying the E2E4 phenotype, the statine did not seemed to have a major effect.

The number of probands is in agreement with the frequency reported in literature. A possible interaction of the effect of statine with the apo E2 isoform is discussed.