Lipoprotein abnormalities

Lipoprotein abnormalities that increase the risk of heart
disease may be secondary to dietary factors, but often follow
multifactorial inheritance. About 60% of the variability of
plasma cholesterol is genetic in origin, influenced by allelic
variation in many genes including those for ApoE, ApoB,
ApoA1 and hepatic lipase that individually have a small
effect. Familial hypercholesterolaemia (type II
hyperlipoproteinaemia), on the other hand, is dominantly
inherited and may account for 10–20% of all early coronary
heart disease. One in 500 of the general population is
estimated to be heterozygous for the mutant LDLR gene. The
risk of coronary heart disease increases with age in
heterozygous subjects, who may also have xanthomas. Severe
disease, often presenting in childhood, is seen in homozygous
subjects.