title: Sucrase-isomaltase deficiency in humans. Different mutations disrupt intracellular transport, processing, and function of an intestinal brush border enzyme.
abstract: Eight cases of congenital sucrase-isomaltase deficiency were studied at the subcellular and protein level with monoclonal antibodies against sucrase-isomaltase. At least three phenotypes were revealed: one in which sucrase-isomaltase protein accumulated intracellularly probably in the endoplasmic reticulum, as a membrane-associated high-mannose precursor, one in which the intracellular transport of the enzyme was apparently blocked in the Golgi apparatus, and one in which catalytically altered enzyme was transported to the cell surface. All patients expressed electrophoretically normal or near normal high-mannose sucrase-isomaltase. The results suggest that different, probably small, mutations in the sucrase-isomaltase gene lead to the synthesis of transport-incompetent or functionally altered enzyme which results in congenital sucrose intolerance.
authors.affiliation: Department of Gastroenterology, Children's Hospital, Bern, Switzerland.
authors.forename: H Y
authors.initials: HY
authors.lastname: Naim
authors.forename: J
authors.initials: J
authors.lastname: Roth
authors.forename: E E
authors.initials: EE
authors.lastname: Sterchi
authors.forename: M
authors.initials: M
authors.lastname: Lentze
authors.forename: P
authors.initials: P
authors.lastname: Milla
authors.forename: J
authors.initials: J
authors.lastname: Schmitz
authors.forename: H P
authors.initials: HP
authors.lastname: Hauri
mesh_terms: D000293:Adolescent; D000328:Adult; D001692:Biological Transport; D001826:Body Fluids / Q000201:enzymology*; D002648:Child; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007413:Intestinal Mucosa / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology; D007424:Intracellular Fluid / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology; D008297:Male; D008871:Microvilli / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology; D009097:Multienzyme Complexes / Q000172:deficiency*; D009154:Mutation; D010641:Phenotype; D012323:RNA Processing, Post-Transcriptional; D013394:Sucrase-Isomaltase Complex / Q000172:deficiency* / Q000302:isolation & purification / Q000502:physiology; D013395:Sucrose / Q000008:administration & dosage; D013577:Syndrome; D014430:Twins, Monozygotic
chemical_list: D009097:Multienzyme Complexes; D013395:Sucrose; D013394:Sucrase-Isomaltase Complex