Nephrocalcinosis in glucose-galactose malabsorption: nephrocalcinosis and proximal tubular dysfunction in a young infant with a novel mutation of SGLT1.
We investigated the molecular mechanisms of genetic variations in SGLT1 that cause glucose-galactose malabsorption (GGM) defects using the crystal structure of vSGLT as a model sugar transporter.
A missense mutation in the Na(+)/glucose cotransporter gene SGLT1 in a patient with congenital glucose-galactose malabsorption: normal trafficking but inactivation of the mutant protein.
Two proband siblings with GGM were previously demonstrated to contain a missense mutation (D28N) in the Na(+)-dependent glucose/galactose cotransporter (SGLT1) that accounts for the defect in sugar absorption.
Sequence analysis of the 15 protein-coding exons and the corresponding exon-intron boundaries of SLC5A1 gene revealed four homozygous missense mutations, c.152A>G (p.N51S), c.1231G>A (p.A411T), c.1673G>A (p.R558H), and c.1845C>G (p.H615Q), that co-segregate with the GGM phenotype in all of the affected individuals.
In the intestine, uptake of dietary glucose is for its majority mediated by SGLT1, and humans with mutations in the SGLT1 gene show glucose/galactose malabsorption.
Mutations in SGLT1 are associated with glucose-galactose malabsorption, SGLT2 with familial renal glucosuria (FRG), and GLUT2 with Fanconi-Bickel syndrome.
A missense mutation in the Na(+)/glucose cotransporter gene SGLT1 in a patient with congenital glucose-galactose malabsorption: normal trafficking but inactivation of the mutant protein.
An SGLT1 missense mutation underlies hereditary glucose/galactose malabsorption, characterized by potentially fatal diarrhea; conversely, oral rehydration therapy exploits normal transport to alleviate life-threatening diarrhea of infectious origin.
Sequence analysis of the amplified products has revealed a single missense mutation in SGLT1 which cosegregates with the GGM phenotype and results in a complete loss of Na(+)-dependent glucose transport in Xenopus oocytes injected with this complementary RNA.
Sequence analysis of the amplified products has revealed a single missense mutation in SGLT1 which cosegregates with the GGM phenotype and results in a complete loss of Na(+)-dependent glucose transport in Xenopus oocytes injected with this complementary RNA.
Loss-of-function mutations in the SGLT1 (sodium/glucose co-transporter-1) gene result in a rare glucose/galactose malabsorption disorder and neonatal death if untreated.
Mutations in SGLT1 are associated with glucose-galactose malabsorption, SGLT2 with familial renal glucosuria (FRG), and GLUT2 with Fanconi-Bickel syndrome.
Effects associated with the loss of SGLT1 on pancreatic islet (cyto) morphology and function were investigated by analyzing islets of a SGLT1 knockout mouse model, that were fed a glucose-deficient, fat-enriched diet (SGLT1<sup>-/-</sup>-GDFE) to circumvent the glucose-galactose malabsorption syndrome.