Genetics and epidemiology of adult-type hypolactasia with emphasis on the situation in Europe

Abstract

The decline in gastrointestinal lactase activity, adult-type hypolactasia, is genetically determined by a recessive single gene. A genetic selection associated with the consumption of milk or milk products for hundreds or thousands of years explains the differences in the prevalence of hypolactasia seen nowadays. The lowest European prevalence has been reported in Denmark (4%) and the highest prevalence in the Mari population in Russia (81%). Key words: Hypolactasia, lactase, lactose intolerance