OBSOLETE: Congenital sucrase-isomaltase deficiency with starch intolerance

Congenital sucrase-isomaltase deficiency (CSID) with starch intolerance is a rare inherited digestive disorder. This entry is now considered obsolete in medical classification systems, as it has been merged into the broader category of congenital sucrase-isomaltase deficiency. In this condition, the body lacks or has reduced levels of two important digestive enzymes — sucrase and isomaltase — that are normally found in the lining of the small intestine. Sucrase breaks down table sugar (sucrose), while isomaltase helps break down starches and certain complex sugars. When these enzymes are missing or not working properly, undigested sugars and starches pass into the large intestine, where bacteria ferment them, causing uncomfortable symptoms. People with this condition typically experience watery diarrhea, bloating, gas, abdominal cramps, and nausea after eating foods containing sucrose (table sugar) or starch. In the variant with starch intolerance, patients also have difficulty digesting starchy foods like bread, potatoes, rice, and pasta, which can make dietary management more challenging. Symptoms usually begin in infancy when babies are first introduced to fruits, juices, or formula containing sucrose, and when starchy foods are added to the diet. Treatment focuses on dietary modification — limiting or avoiding foods high in sucrose and starch — and enzyme replacement therapy. An FDA-approved enzyme supplement called sacrosidase (brand name Sucraid) can help break down sucrose, though it does not address starch intolerance directly. With proper management, most people with this condition can lead healthy lives, though lifelong dietary awareness is necessary.

Bring these to your next appointment

• Q1.How severe is my child's enzyme deficiency, and does it include starch intolerance?,Should we do genetic testing to confirm the diagnosis and identify the specific mutation?,Is sacrosidase (Sucraid) appropriate for my child, and how should it be dosed?,Can you refer us to a dietitian experienced with sucrase-isomaltase deficiency?,What foods are safe to eat, and are there any starchy foods that might be better tolerated?,Will my child's tolerance for sugar and starch improve as they get older?,Should other family members be tested for this condition?

Common questions about OBSOLETE: Congenital sucrase-isomaltase deficiency with starch intolerance

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