Meta-Biol

• Pathways

Mutations that disrupt the catalytic activity of LCT (lactase) block the cleavage of lactose (Lac) to galactose and glucose in the gut lumen and cause lactose intolerance in nursing infants. Affected individuals can develop severe diarrhea; the disease can be effectively managed by complete exclusion of lactose from the diet. A variety of LCT mutant alleles have been described. Two missense mutations that are associated with severe loss of lactase activity in vivo are annotated here (Kuokkanen et al. 2006; Torniainen et al. 2009).