Congenital maltase-glucoamylase deficiency associated with lactase and sucrase deficiencies

Buford L. Nichols*, Stephen E. Avery, Wikrom Karnsakul, Farook Jahoor, Partha Sen, Dallas M. Swallow, Ursula Luginbuehl, Dagmar Hahn, Erwin E. Sterchi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Background: Multiple enzyme deficiencies have been reported in some cases of congenital glucoamylase, sucrase, or lactase deficiency. Here we describe such a case and the investigations that we have made to determine the cause of this deficiency. Methods and Results: A 2.5 month-old infant, admitted with congenital lactase deficiency, failed to gain weight on a glucose oligomer formula (Nutramigen®). Jejunal mucosal biopsy at 4 and 12 months revealed normal histology with decreased maltase-glucoamylase, sucrase-isomaltase, and lactase-phlorizin hydrolase activities. Testing with a 13C-starch/breath 13CO2 loading test confirmed proximal starch malabsorption. Sequencing of maltase-glucoamylase cDNA revealed homozygosity for a nucleotide change (C1673T) in the infant, which causes an amino acid substitution (S542L) 12 amino acids after the N-terminal catalytic aspartic acid. The introduction of this mutation into "wildtype" N-terminus maltase-glucoamylase cDNA was not associated with obvious loss of maltase-glucoamylase enzyme activities when expressed in COS 1 cells and this amino-acid change was subsequently found in other people. Sequencing of the promoter region revealed no nucleotide changes. Maltase-glucoamylase, lactase, and sucrase-isomaltase were each normally synthesized and processed in organ culture. Conclusions: The lack of evidence for a causal nucleotide change in the maltase-glucoamylase gene in this patient, and the concomitant low levels of lactase and sucrase activity, suggest that the depletion of mucosal maltase-glucoamylase activity and starch digestion was caused by shared, pleiotropic regulatory factors.

Original languageEnglish (US)
Pages (from-to)573-579
Number of pages7
JournalJournal of pediatric gastroenterology and nutrition
Issue number4
StatePublished - Oct 2 2002
Externally publishedYes


  • Lactase-phlorizin hydrolase
  • Maltase-glucoamylase
  • Sucrase-isomaltase

ASJC Scopus subject areas

  • Gastroenterology
  • Pediatrics, Perinatology, and Child Health


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