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Genetic and Rare Diseases Information Center (GARD)

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Congenital sucrase-isomaltase deficiency

Other Names for this Disease
  • Congenital sucrose-isomaltase malabsorption
  • CSID
  • Disaccharide intolerance, 1
  • SI deficiency
  • Sucrase-isomaltase deficiency, congenital
More Names
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What are the signs and symptoms of congenital sucrase-isomaltase deficiency (CSID)?

Affected infants usually develop symptoms soon after they first ingest sucrose, which is found in modified milk formulas, fruits, or starches. Symptoms may include explosive, watery diarrhea resulting in abnormally low levels of body fluids (dehydration), abdominal swelling (distension), and/or abdominal discomfort. In addition, some affected infants may experience malnutrition, resulting from malabsorption of essential nutrients, and/or failure to thrive, resulting from nutritional deficiencies. In some cases, individuals may exhibit irritability; colic; abrasion and/or irritation (excoriation) of the skin on the buttocks as a result of prolonged diarrhea episodes; and/or vomiting.[1]

Symptoms of this disorder vary among affected individuals, but are usually more severe in infants and young children than in adults. Symptoms exhibited in infants and young children are usually more pronounced than those of the affected adults because the diet of younger individuals often includes a higher carbohydrate intake. In addition, the time it takes for intestinal digestion is less in infants or young children.[1]
Last updated: 5/17/2011

  1. Disaccharide Intolerance I. National Organization for Rare Disorders. April 25, 2008; Accessed 7/5/2013.