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Mosaic pattern of sucrase isomaltase deficiency in two brothers

Konrad Reinshagen1, Klaus M Keller, Bianca Haase

  • 1Department of Pediatric Surgery, University of Heidelberg, D-68167 Mannheim, Germany.

Pediatric Research
|November 29, 2007
PubMed

Insights

Two brothers with sucrase isomaltase (SI) deficiency experienced weight loss and digestive issues. Their duodenal biopsies revealed a mosaic pattern of SI deficiency, impacting sucrose digestion.

Area of Science:

  • Gastroenterology
  • Human Genetics
  • Molecular Biology

Background:

  • Chronic protracted diarrhea in infants often involves poorly understood mucosal changes.
  • Sucrase isomaltase (SI) deficiency is a rare genetic disorder affecting carbohydrate digestion.

Observation:

  • Two brothers presented with weight loss and dyspepsia after sucrose intake.
  • Hydrogen breath tests indicated abnormal sucrose digestion in one sibling.
  • Duodenal biopsies showed reduced lactase and SI expression.

Findings:

  • Immunoelectron microscopy revealed an isolated SI deficiency in a mosaic pattern within enterocytes.
  • Enterocytes displayed reduced SI on microvilli, but normal levels of other disaccharidases like lactase and aminopeptidase N (ApN).
  • This mosaic pattern suggests distinct cellular mechanisms for the expression and transport of brush border enzymes.

Implications:

  • Findings suggest unique post-translational or transport mechanisms for individual brush border enzymes.
  • The mosaic distribution may indicate differential clonal expression or a lack of coordinated control over hydrolase expression.
  • Further research is needed to determine if this pattern is developmental or pathological.

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