Congenital sucrase-isomaltase deficiency is a rare inborn error of metabolism (IEM) and autosomal recessive disorder caused by mutatins in the SI gene which encodes for the enzyme sucrase-isomaltase. Sucrase-isomaltase catalyzes the breakdown of sucrose, maltose and larger carbohydrates. Sucrose and maltose are disaccharides, and are broken down into simple sugars during digestion. Sucrose is broken down into glucose and fructose, while maltose is broken down into two glucose molecules. This disorder is characterized by stomach cramps, bloating, excess gas production, and diarrhea after ingestion of sucrose and maltose. These digestive problems can lead to failure to thrive and malnutrition. There is no cure for Sucrase-Isomaltase Deficiency, however orally administrated Sacrosidase can help relieve symptoms. Similarly, restricting high sugar diets can also help. Most affected children are better able to tolerate sucrose and maltose as they get older. Frequency of Sucrase-Isomaltase Deficiency is about 1 in 5,000 with European descent. 

Sucrase-Isomaltase Deficiency References

Starch and Sucrose Metabolism References