Congenital Sucrase Isomaltase Deficiency

Congenital Sucrase Isomaltase Deficiency (CSID) has an extensive review in a recent JPGN supplement (JPGN 2012; supplement 2: S1-47).

A concise update of the clinical aspects is provided by William Treem (S7-S13).   Specific points that he makes includes the following:

  • CSID was first described in 1960 by Weijers and colleagues
  • Sucrase-isomaltase gene (3q25-26) identified in 1992; now more than 55 mutations have been described.  At least one of the four most common mutations are identified in about 80% of affected individuals.
  • Prevalence: estimates range from 1 in 500 to 1 in 2000 in caucasians; the prevalence is lower in other populations.  Some patients suspected of having CSID may be heterozygotes with low enzyme activity (but not truly deficient).
  • Clinical features determined by degree of enzyme deficiency and amount of sugar and starch consumed.  In the U.S. typically 60% of calories consumed are derived from carbohydrates and 30% from sucrose.  A typical U.S. adult consumes 150 lb of sugar per year.
  • Classical presentation: severe watery diarrhea and poor weight gain in a 9- to 18-month old after exposure to juices, baby foods/fruits, and other starches.
  • Other symptoms: gas/bloating, abdominal pain, irritable bowel syndrome
  • Diagnosis: intestinal biopsy analysis.  A potential pitfall includes mishandling of biopsy specimens. An alternative means of diagnosis is the 13-C sucrose breath test.
  • Treatment: 1. dietary avoidance results in improvement in many, though only 10% respond fully to diet. 2. enzymatic treatment. Baker’s yeast (Saccharomyces cerevisiae) contains a sucrase.  Development of sacrosidase (Sucraid) from Baker’s yeast has allowed 81% of patients to consume an unrestricted diet.  Dosing: 1 mL with meals/snacks if <15 kg and 2 mL if >15 kg.
  • Despite sacrosidase treatment, 27% of patients required strict sucrose restriction with either mild or strict starch restriction to maintain acceptable suppression of symptoms.
  • What is not noted in this summary–cost information: sucraid may cost as much as $3700 per month.  A similar product in Europe costs about $400 per month

Multiple other articles in this supplement address related subjects.

On page S31, information is given from parent support group.  This parent support group (CSIDinfo.com) offers dietary advice specific for each phenotype (A,B,C,D and F) which is based on their disaccharidase levels, ability to outgrow symptoms, and tolerance of starch and maltodextrins.

On page S34, the major genetic mutations are discussed.  Use of genetic testing will detect the majority with CSID which could become an alternative means of diagnosing CSID in this population.

Additional Information