How Does CSID Differ from Lactose Intolerance?

Congenital Sucrase-Isomaltase Deficiency (CSID) is similar to lactose intolerance, a well-known carbohydrate malabsorption condition, although the two conditions are treated differently. The table below compares CSID to lactose intolerance.

 

LACTOSE INTOLERANCECSID
Lactose intolerance is the small intestine's inability to digest lactose due to a lack of the enzyme lactase.CSID is the small intestine's inability to digest sucrose due to a lack of the enzyme sucrase.
Lactose is a type of carbohydrate found in milk and other dairy products.Sucrose is a type of carbohydrate, commonly referred to as table sugar, and is naturally found in many fruits and vegetables. Sucrose is a common additive in many processed foods.
Ingestion of milk sugars causes gastrointestinal symptoms similar to those in CSID.Ingestion of sucrose causes gastrointestinal symptoms, most commonly diarrhea, bloating, abdominal pain, or gas.
Lactose intolerance is typically not caused by a genetic mutation and is very common. There is a rare form of lactose intolerance present at birth known as congenital lactose deficiency, which is caused by a genetic mutation.CSID is caused by a mutation of a gene in chromosome 3, producing a deficiency of sucrase enzymatic activity, making the body unable to digest sucrose.
Lactose intolerance is considered very common, excluding the rare congenital lactose deficiency.CSID is a rare disease.
Onset can occur at any age, excluding the rare congenital lactose deficiency, which is present at birth.CSID is congenital, or present at birth.