[Primary lipoprotein lipase deficiency. Study in Quebec].

Primary lipoprotein lipase deficiency is a rare autosomal recessive disease that causes hyperchylomicronaemia complicated by pancreatitis. Recent advances in molecular biology have facilitated its diagnosis and enabled heterozygous subjects to be identified. Numerous mutations are responsible for lipoprotein lipase deficiency. In some eastern regions of Quebec province homozygotes have been found in very high concentrations: up to 200 times the frequency observed in all other parts of the world. Heterozygocity may represent 1 in 40 subjects. Two mutations account for 95 percent of the Quebec cases, and each of them has its own characteristic geographical distribution. These peculiarities have been ascribed to a founder effect suggested by the analysis of the first colons' migrations and by the study of homozygotes' genealogy. Most of the ancestors of the Quebec carriers came from northwestern France in the 17th century, and heterozygotes alleged to be healthy carriers of the trait may have a predisposition to premature development of a cardiovascular disease. Their blood lipid levels and the composition of their lipoproteins (particularly those with low density) are suggestive of an atherogenic potential similar to that of hyperapobetalipoproteinaemia or familial combined hyperlipidaemia. Molecular biology would be a useful tool to confirm or infirm this hypothesis and to identify subjects at risk of developing a cardiovascular disease.