This novel concept and the existence of mild consequences in a number of SI mutants strongly propose that CSID is an underdiagnosed and a more common intestinal disease than currently known.
Immunoelectron microscopy of duodenal biopsies showed an isolated SI deficiency in a mosaic pattern [e.g., 42% (14%) crypt enterocytes and 64% (59%) villus enterocytes with decreased amounts of SI on microvilli], whereas lactase and aminopeptidase n (ApN) were present at the apical membrane of all cells in a normal range.
Variants in the SI gene had previously been described in CSID patients, which cause amino acid exchanges that affect the transport, the processing, or the function of the SI protein.
Variants in the SI gene had previously been described in CSID patients, which cause amino acid exchanges that affect the transport, the processing, or the function of the SI protein.
Variants in the SI gene had previously been described in CSID patients, which cause amino acid exchanges that affect the transport, the processing, or the function of the SI protein.
Variants in the SI gene had previously been described in CSID patients, which cause amino acid exchanges that affect the transport, the processing, or the function of the SI protein.
The cDNA encoding SI from a patient with CSID reveals a mutation in the isomaltase subunit of SI that results in the substitution of a cysteine by an arginine at amino acid residue 635 (C635R).
Biosynthetic labeling and immunoelectron microscopy reveal a predominant localization of SI in the endoplasmic reticulum (ER) similar to phenotype I of CSID.
The impaired sorting profile to the apical membrane of human intestinal sucrase-isomaltase is the underlying cause in the pathogenesis of a novel phenotype of intestinal congenital sucrase-isomaltase deficiency.
The impaired sorting profile to the apical membrane of human intestinal sucrase-isomaltase is the underlying cause in the pathogenesis of a novel phenotype of intestinal congenital sucrase-isomaltase deficiency.
Congenital sucrase-isomaltase deficiency. Identification of a glutamine to proline substitution that leads to a transport block of sucrase-isomaltase in a pre-Golgi compartment.