Maltase-glucoamylase enzyme plays an important role in starch digestion. Glucoamylase deficiency is reported to cause chronic diarrhea in infants, but its role in dyspeptic children is unknown.
Glucoamylase and other disaccharidase specific activities were assayed from duodenal biopsy specimens in 44 children aged 0.5–18 years (mean, 10 ± 5 years) undergoing endoscopy to evaluate dyspeptic symptoms. All subjects had normal duodenal histology. Intestinal organ culture was used to evaluate synthesis and processing of maltase-glucoamylase. Sequencing of the maltase-glucoamylase coding region was performed in subjects with low activity or variation of isoform in organ culture.
Twenty-two of the dyspeptic children had one or more disaccharidases with low specific activity. Twelve subjects (28%) had low activity of glucoamylase. Eight subjects had low activities of glucoamylase, sucrase, and lactase. Low glucoamylase activity was not correlated with the isoform phenotype of maltase-glucoamylase as described by metabolic labeling and sodium dodecyl sulfate electrophoresis. Novel nucleotide changes were not detected in one subject with low glucoamylase activity or in two subjects with variant isoforms of maltase-glucoamylase peptides.
Twelve of 44 dyspeptic children had low specific activity of duodenal maltase-glucoamylase. Eight of these children had low specific activity of all measured disaccharidases.
*USDA Children's Nutrition Research Center, Baylor College of Medicine, and Texas Children's Hospital, Houston, Texas, U.S.A., and Siriraj Hospital, Mahidol University, Bangkok, Thailand; †University of Bern, Bern, Switzerland; ‡USDA Children's Nutrition Research Center, Baylor College of Medicine, and Texas Children's Hospital, Houston, Texas, U.S.A.; and §University of College London, London, United Kingdom
Received March 11, 2002; accepted May 23, 2002.
Supported by the National Institutes of Health, Bethesda, MD, and in part by federal funds from the US Department of Agriculture, Agricultural Research Service, under Cooperative Agreement number 58-6250-1-003 (B.N.), and by the Swiss National Foundation number 3200-052736.97 (E.S.).
Presented at the annual meeting of the Academic Pediatric Societies, Baltimore, MD, April 29–May 1, 2001.
The contents of this publication do not necessarily reflect the views or policies of the US Department of Agriculture, nor does mention of trade names, commercial products, or organizations imply endorsement by the US or Swiss governments.
Address correspondence and reprint requests to Dr. Buford L. Nichols, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street, Houston, TX 77030–2600 (e-mail: firstname.lastname@example.org).