ViennaLab offers a reliable and convenient reverse-hybridization assay for the identification of two polymorphisms (-13910 T/C and -22018 A/G) upstream of the LCT gene and four mutations (del4E4, A149P, A174D, N334K) in the aldolase B gene.
Dietary carbohydrates for humans include polysaccharides (starch), disaccharides (sucrose, lactose) and monosaccharides (glucose, fructose, galactose). During digestion, specific brush border enzymes will initially hydrolyze poly- and disaccharides into their monosaccharide constituents, which subsequently become absorbed by apical cells of the small intestine and further metabolized. A variety of genetically determined enzyme and transporter deficiencies may cause hereditary intolerance to common dietary sugars. Lactose intolerance (lactase non-persistence, adult-type hypolactasia) is an extremely frequent condition caused by the rapid decline of lactase activity after weaning. Undigested lactose is degraded into short-chain fatty acids and gas (CO2, H2) by colonic bacteria, leading to abdominal bloating, diarrhea, nausea and flatulence. In individuals of European descent lactose intolerance is highly associated with two polymorphisms located upstream of the lactase (LCT) gene locus. Hereditary fructose intolerance (HFI) is an autosomal recessive disorder caused by mutations in the aldolase B gene. Affected subjects suffer from severe abdominal pain, vomiting and hypoglycaemia after intake of foods containing fructose. Prolonged ingestion may ultimately lead to death from irreversible liver and kidney damage. Most at risk are infants, who unlike many affected adults have not yet developed aversion to fruits and sweets. The severe condition of HFI due to aldolase B deficiency needs to be distinguished from the milder and more common fructose malabsorption, the molecular basis of which has not yet been elucidated.