Heterozygotes Are a Potential New Entity among Homozygotes and Compound Heterozygotes in Congenital Sucrase-Isomaltase Deficiency

Nutrients. 2019 Sep 25;11(10):2290. doi: 10.3390/nu11102290.

PMID: 31557950

Diab M. Husein, Dalanda Wanes, Lara M. Marten, Klaus-Peter Zimmer and Hassan Y. Naim

Summary: In this study, heterozygote mutation carriers in CSID were proposed as a new entity, possibly presenting with milder symptoms. It is suggested that the heterozygote mutants may affect the disease development and treatment.

Abstract

Objective: Congenital sucrase-isomaltase deficiency (CSID) is an autosomal recessive disorder of carbohydrate maldigestion and malabsorption caused by mutations in the sucrase-isomaltase (SI) gene. Previous research has well described the effects of homozygote and compound heterozygote inheritance trait of SI mutations in CSID patients. In this study, heterozygote mutation carriers in CSID were proposed as a new entity, possibly presenting with milder symptoms.

Results: Recent observations show heterozygote mutation carriers among patients with CSID or patients diagnosed with functional gastrointestinal disorders. Recent studies implicate significant phenotypic heterogeneity depending on the mutation and more research is needed regarding the correlation of genetics, function at the cellular and molecular level and clinical presentation.

Conclusion: The increased importance of SI gene variants in irritable bowel syndrome (IBS) or other functional gastrointestinal disorders (FGIDs) and their available symptom relief diets like fermentable oligo-, di-, mono-saccharides and polyols (FODMAPs) suggest that the heterozygote mutants may affect the disease development and treatment.