Genetic and acquired sucrase-isomaltase deficiency: A clinical review

J Pediatr Gastroenterol Nutr. 2024 Apr;78(4):774-782. doi: 10.1002/jpn3.12151.Epub 2024 Feb 8.


Tanaz Farzan Danialifar 1 2Bruno P Chumpitazi 3 4Devendra I Mehta 5Carlo Di Lorenzo 6


Author information

1Children's Hospital Los Angeles, Los Angeles, California, USA.

2Keck School of Medicine of USC, Los Angeles, California, USA.

3Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA.

4Duke Clinical Research Institute, Durham, North Carolina, USA.

5Center for Digestive Health and Nutrition, Arnold Palmer Hospital for Children, Orlando, Florida, USA.

6Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Nationwide Children's Hospital, Columbus, Ohio, USA.


Genetic sucrase-isomaltase deficiency (GSID) is an inherited deficiency in the ability to digest sucrose and potentially starch due to mutations in the sucrase-isomaltase (SI) gene. Congenital sucrase-isomaltase deficiency is historically considered to be a rare condition affecting infants with chronic diarrhea as exposure to dietary sucrose begins. Growing evidence suggests that individuals with SI variants may present later in life, with symptoms overlapping with those of irritable bowel syndrome. The presence of SI genetic variants may, either alone or in combination, affect enzyme activity and lead to symptoms of different severity. As such, a more appropriate term for this inherited condition is GSID, with a recognition of a spectrum of severity and onset of presentation. Currently, disaccharidase assay on duodenal mucosal tissue homogenates is the gold standard in diagnosing SI deficiency. A deficiency in the SI enzyme can be present at birth (genetic) or acquired later, often in association with damage to the enteric brush-border membrane. Other noninvasive diagnostic alternatives such as sucrose breath tests may be useful but require further validation. Management of GSID is based on sucrose and potentially starch restriction tailored to the individual patients' tolerance and symptoms. As this approach may be challenging, additional treatment with commercially available sacrosidase is available. However, some patients may require continued starch restriction. Further research is needed to clarify the true prevalence of SI deficiency, the pathobiology of single SI heterozygous mutations, and to define optimal diagnostic and treatment algorithms in the pediatric population.

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