Congenital Sucrase-Isomaltase Deficiency (CSID)

Congenital sucrose-isomaltase deficiency (CSID) is a rare disorder that affects a person’s ability to digest certain sugars. People with this condition cannot break down the sugars found in fruits and table sugar (sucrose), sugar found in grains (maltose), and other compounds made from these sugar molecules (carbohydrates).

CSID doesn’t usually show up in infants until it is weaned and starts to eat fruits, juices and grains. Chronic, watery diarrhea and failure to gain weight and grow at the expected rate (failure to thrive) are the most common symptoms in infants and toddlers. Other symptoms include abdominal pain and distention, gassiness, colic, irritability, area where the skin is torn or worn off on the buttocks (excoriated), diaper rash and vomiting.

How is CSID diagnosed?

Symptoms are similar to other common gastrointestinal disorders, so the true number of people with CSID may not be diagnosed. Many times a patient is thought to have a food allergy or unable to have cow’s milk or soy protein. Once a child is a little older, and a larger variety of foods are eaten, it is more difficult to correctly identify sucrose as the cause of symptoms.

There are a few ways to diagnose CSID:

  • Stool sample to determine pH
  • Sucrose Breath Test
  • Small Bowel Disaccharidase Measurement
  • Trial using Sucraid medicine to assess response.

Treatment options

In patients with CSID and overt symptoms that need treatment, there are two ways: using a drug and not using a drug. Until a recent drug was developed for CSID, the only way to treat CSID was staying on a strict sucrose-free diet. It is seldom necessary to make this diet starch-free except in infants or in patients where a sucrose-free diet does not provide enough relief of symptoms.

The second treatment option is using a drug called Sucraid. Sucraid is an effective, simple-to-give option for the management of sucrose deficiency that reduces or eliminates both the need for dietary restrictions and the symptoms of CSID in the majority of patients.