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Sucrase-Isomaltase Deficiency

Congenital sucrase-isomaltase deficiency (CSID) is a rare genetic disorder that affects an individual’s ability to digest certain sugars. People with CSID have low levels of two digestive enzymes -  sucrase and isomaltase.  These enzymes are responsible for the breakdown of the sugars sucrose (table sugar) and maltose (sugar found in grains).   The inability to metabolize sucrose and maltose leads to severe abdominal symptoms such as severe diarrhea, cramps, bloating, excess gas, decreased weight gain, and growth failure.  The symptoms of CSID usually become apparent when an infant is weaned and begins consuming foods such as fruits, juices, and grains. Symptoms are also more severe in infants and young children than adults as their diet contains a higher amount of carbohydrates, including sucrose and maltose. 

Congenital sucrase-isomaltase deficiency is believed to affect between 1 in 500 to 2000 non-Hispanic Caucasians in North America and Europe. It most common among native populations of Greenland, Alaska, and Canada where an estimated 1 in 20 children are affected.1

Dietary management through a low-sucrose and starch (maltose) or sucrose-starch free diet is advised, especially in the first few years of life.   Severity of symptoms and the amount of dietary restriction required varies by patient.  Without enzyme replacement, symptom control can difficult to achieve while still meeting the nutritional needs of the growing child.

Current drug therapy at Accredo for Congenital Sucrase Isomaltase Deficiency includes:

  • Sucraid
    • Sucraid is approved by the US Food and Drug Administration (FDA) for the treatment of congenital sucrase isomaltase deficiency (genetically determined sucrase deficiency).


1. Treem, William R. "Congenital sucrase-isomaltase deficiency." Journal of pediatric gastroenterology and nutrition 21.1 (1995): 1-14.


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