Prevalence of CSID

The prevalence of CSID is not known with certainty due to the phenotypic variations described previously. Studies have tried to account for the number of heterozygote carriers in the general population based on measurements of sucrase activity in small bowel biopsy specimens. Peterson and Herber reported an 8.9% frequency of heterozygotic individuals in a sampling of the general US population. Welsh et al found only a 2% incidence of heterozygotic individuals in a more specific caucasian population.

The absence of sucrase activity in patients as young as four months of age and symptoms in patients with CSID appearing as soon as sucrose is introduced to the diet, support the idea that this deficiency is present at birth.

The Prevalence of CSID in Various Populations

• Group

• Greenland Eskimos
• Native Alaskans
• Canadian Native Peoples
• Danes
• North Americans

•  

• Percentage

• 2-10%
• 3.0%
• 3.6-7.1%
• <0.1%
• <0.2%

Up to 10% of the Greenland eskimo population was found to be homozygotes and consequently affected by the disease. The high prevalence in some populations could be the result of biological mutations produced by those who do not traditionally ingest sucrose containing foods. Isolated from a western style diet, this has not been a clinical problem, but the migration of western dietary culture now means that CSID symptoms may be experience by these populations.

Although rare in the US, 1 in a 1000 patients have some degree of SI deficiency and the similarity of S-I deficiency symptoms to those of other conditions and diseases makes it conceivable that it is misdiagnosed or under- diagnosed both in children and adults as conditions such as toddler’s diarrhea or Irritable Bowel Syndrome.