Diseases & Conditions


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Disaccharide Intolerance I


Synonyms of Disaccharide Intolerance I
  • Congenital Sucrose Isomaltose Malabsorption
  • CSID
  • SI Deficiency
  • Sucrase-Isomaltase Deficiency, Congenital
  • Sucrose Intolerance, Congenital

Disorder Subdivisions



    General Discussion
    Disaccharide intolerance I is a rare inherited metabolic disorder characterized by the deficiency or absence of the enzymes sucrase and isomaltase. This enzyme complex (sucrase-isomaltase) assists in the breakdown of a certain sugars (i.e., sucrose) and certain products of starch digestion (dextrins). The sucrase-isomaltase enzyme complex is normally found within the tiny, finger-like projections (microvilli or brush border) lining the small intestine. When this enzyme complex is deficient, nutrients based on ingested sucrose and starch cannot be absorbed properly from the gut.

    Symptoms of this disorder become evident soon after sucrose or starches, as found in modified milk formulas with sucrose or polycose, are ingested by an affected infant. Breast-fed infants or those on lactose-only formula manifest no symptoms until such time as sucrose (found in fruit juices, solid foods, and/or some medications) is introduced into the diet. Symptoms are variable among affected individuals but usually include watery diarrhea, abdominal swelling (distension) and/or discomfort, among others. Intolerance to starch often disappears within the first few years of life and the symptoms of sucrose intolerance usually improve as the affected child ages. Disaccharide intolerance I is inherited as an autosomal recessive genetic trait.

    Organizations related to Disaccharide Intolerance I
    • CLIMB (Children Living with Inherited Metabolic Diseases)
      Climb Building
      Crewe Intl CW2 6BG
      Phone #: +44- 87-0 7700 325
      800 #: --
      e-mail: info@climb.org.uk
      Home page: http://www.CLIMB.org.uk
    • CSID Parent Support Group
      26521 SE 19th Court
      Sammamish WA 98075
      Phone #: 425-394-1066
      800 #: --
      e-mail: deansl@msn.com
      Home page: http://www.csidinfo.com
    • MUMS (Mothers United for Moral Support, Inc) National Parent-to-Parent Network
      150 Custer Court
      Green Bay WI 54301-1243
      Phone #: 920-336-5333
      800 #: 877-336-5333
      e-mail: mums@netnet.net
      Home page: http://www.netnet.net/mums/
    • March of Dimes Birth Defects Foundation
      1275 Mamaroneck Avenue
      White Plains NY 10605
      Phone #: 914-428-7100
      800 #: 888-663-4637
      e-mail: Askus@marchofdimes.com
      Home page: http://www.marchofdimes.com



    For a Complete Report

    This is an abstract of a report from the National Organization for Rare Disorders, Inc. ? (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html