Small bowel (small intestine)
Disaccharidase (lactase) deficiency

Topic Completed: 1 August 2012

Revised: 8 March 2019

Copyright: 2003-2019,, Inc.

PubMed Search: Disaccharidase lactase deficiency small bowel

Hanni Gulwani, M.B.B.S.
Page views in 2018: 280
Page views in 2019 to date: 286
Cite this page: Gulwani H. Disaccharidase (lactase) deficiency. website. Accessed November 11th, 2019.
Definition / general
  • Disaccharidases are located in apical cell membrane of villous absorptive epithelial cells

Congenital deficiency:
  • Rare; malabsorption evident with milk feeding, which causes explosive, watery, frothy stools and abdominal distention

Acquired deficiency:
  • Common in North American blacks
  • Causes osmotic diarrhea
  • Acquired deficiency of lactase also occurs in duodenal mucosa of children with celiac disease (J Gastroenterol Hepatol 2008;23:e348)
  • Increased hydrogen in breath test due to bacterial fermentation of undigested lactose
  • Dietary elimination of milk and milk products
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