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Hypomorphic SI genetic variants are associated with childhood chronic loose stools

Bruno P Chumpitazi1, Jeffery Lewis2, Derick Cooper3

  • 1Baylor College of Medicine, Houston, TX, United States of America.

Plos One
|May 21, 2020
PubMed

Insights

Congenital sucrase-isomaltase deficiency (CSID) variants are more common in children with chronic loose stools. These genetic variants are linked to a greater gastrointestinal symptom burden in affected children.

Area of Science:

  • Genetics
  • Gastroenterology
  • Biochemistry

Background:

  • The SI gene encodes sucrase-isomaltase, an enzyme crucial for carbohydrate digestion in the intestinal brush border.
  • Hypomorphic variants in the SI gene are associated with recessive congenital sucrase-isomaltase deficiency (CSID), leading to gastrointestinal distress.
  • Chronic, idiopathic loose stools in children can be indicative of underlying digestive disorders like CSID.

Purpose of the Study:

  • To determine the prevalence of CSID-associated SI variants in children with chronic idiopathic loose stools.
  • To compare this prevalence against the general population.
  • To assess the gastrointestinal symptom burden associated with SI genotype within the pediatric study cohort.

Main Methods:

  • A prospective study enrolled 308 non-Hispanic white children (≤18 years) with chronic, idiopathic loose stools.
  • Genotyping was performed to identify 37 hypomorphic SI variants.
  • Data from the Exome Aggregation Consortium (ExAC) served as the general population reference.

Main Results:

  • The cumulative prevalence of hypomorphic SI variants was significantly higher in the study group (4.5%) compared to the general population (1.3%).
  • Children with hypomorphic SI variants experienced a more severe gastrointestinal symptom burden.
  • This included more frequent loose stools, higher overall stool frequency, looser stool consistency, and increased flatulence.

Conclusions:

  • Non-Hispanic white children with chronic idiopathic loose stools exhibit a higher prevalence of CSID-associated hypomorphic SI variants than the general population.
  • A significant association exists between hypomorphic SI variants and an increased gastrointestinal symptom burden in these children.
Abstract

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