congenital lactase deficiency
congenital lactase deficiency
A rare, autosomal recessive gastrointestinal disorder (OMIM:223000) characterised by severe watery diarrhoea in infants fed with breast milk or other lactose-containing formulas. A virtually complete lack of LCT activity is found in jejunal biopsy material.In contrast, adult-type hypolactasia (lactose intolerance), the most common enzyme deficiency worldwide, is due to a developmental downregulation of lactase activity that evolves from childhood to early adulthood, and which is regarded as a normal physiological phenomenon. Most northern Europeans maintain lactase activity and digest lactose throughout life, a phenomenon known as lactase persistence.
Molecular pathology
Defects of LCT, which encodes lactase, a glycosyl hydrolase, cause congenital lactase deficiency.