Kaur, KamaljitMahmood, SafrunMahmood, Akhtar2006-10-012009-05-272006-10-012009-05-272006-10-01Kaur K, Mahmood S, Mahmood A. Hypolactasia as a molecular basis of lactose intolerance. Indian Journal of Biochemistry & Biophysics. 2006 Oct; 43(5): 267-74http://imsear.searo.who.int/handle/123456789/2686592 references.Lactase-phlorizin hydrolase (LPH), a membrane-bound glycoprotein present in the luminal surface of enterocytes in the intestine is responsible for lactose intolerance, a phenomenon prevalent in humans worldwide. In the rodent intestine, the post-natal development of the LPH follows a specific pattern, such that the enzyme levels are high in the peri-natal period, but declines considerably upon maturation. The observed maturational decline in the LPH activity is very similar to adult-type hypolactasia observed in humans. Majority of the studies have been carried out using animal models or cell lines and a number of hypotheses have been put forward to explain the maturational decline of lactase activity such as: (a) decreased amount of lactase protein, (b) defect in post-translational modification of precursor lactase to the mature enzyme, and (c) synthesis of an inactive, high molecular weight lactase with altered glycosylation, however, the precise underlying mechanism of adult-type hypolactasia remains undefined. The present review describes the recent developments in understanding the regulation of lactase expression and the possible mechanism of adult-type hypolactasia, as a cause of lactose intolerance.engAnimalsGene Expression Regulation, EnzymologicGlycosylationGlycosylceramidase --chemistryHumansLactase --biosynthesisLactose --geneticsLactose Intolerance --etiologyPolymorphism, GeneticJournal Article