Genealogy and regional distribution of lipoprotein lipase deficiency in French-Canadians of Quebec.

Lipoprotein lipase (LPL) deficiency, an autosomal recessive disorder causing chylomicronemia, has a high prevalence in the French-Canadian population of Quebec. The molecular basis of LPL deficiency has been defined, and two major mutations have been shown to have an uneven geographic distribution. Two mutations, one at residue 188 (M-188) and the other at residue 207 (M-207), are described here; they account for 95% of the mutant alleles. The carrier rate of M-188 was highest in western Quebec (1/326) but that of M-207 was much higher in the eastern part of the province (1/85). Genealogical reconstruction has revealed that both mutations were introduced to the French-Canadian population by migrants from France in the seventeenth century. M-188 is likely to have a Scottish ancestor, whereas M-207 appears to be of French origin.