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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #155207
Title: COEXISTENCE OF GLUCOAMYLASE WITH OTHER DISACCHARIDASE DEFICIENCIES

Author
item NICHOLS, BUFORD - BAYLOR COLL OF MEDICINE
item AVERY, STEPHEN - BAYLOR COLL OF MEDICINE
item FRALEY, J. - BAYLOR COLL OF MEDICINE
item GILGER, MARK - BAYLOR COLL OF MEDICINE
item ADAMS, BRIDGET - STATE UNIV NEW YORK
item BAKER, SUSAN - STATE UNIV NEW YORK

Submitted to: Gastroenterology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2003
Publication Date: 10/1/2003
Citation: NICHOLS, B.L., AVERY, S.E., FRALEY, J.K., GILGER, M., ADAMS, B., BAKER, S.S. COEXISTENCE OF GLUCOAMYLASE WITH OTHER DISACCHARIDASE DEFICIENCIES. GASTROENTEROLOGY. 2003.

Interpretive Summary: Starch contributes up to 80% of energy calories in the human diet. Maltase-glucoamylase is the final enzyme in the conversion of starch into glucose for absorption. Deficiencies of lactase and sucrase are well described in the literature, but glucoamylase has been poorly studied. This paper determines the normal values for glucoamylase and classifies the types of glucoamylase deficiency. Ninety percent of all glucoamylase deficiencies coexist with the deficiency of at least one other dissacharidase. While some of these pandeficiencies can be attributed to histologic damage to the mucosa, a large number occur with normal histology. The mechanisms for multiple dissacharidase deficiency with normal histology are unknown, but probably represents a co-regulation of genes controlling dissacharidase activities.

Technical Abstract: Background and Aims: Lactose, sucrose, maltose, and palatinose substrates are routinely used with assays to detect deficiencies of lactase and sucrase in clinical mucosal biopsies. A study was conducted to determine the reference value, frequency of deficient values and types of glucoamylase clinical deficiency. Methods: Glucoamylase activity was assayed using glucose oligomers as substrate. This assay was added to a series of 980 clinical biopsy homogenates assayed for lactase, sucrase, maltase, and palatinase activities. Activities were converted to Z scores to standardize comparisons. Results: The reference value (Z score <1, -1 SD of mean) for normal glucoamylase activity was 35 U/g proteins (n = 673). There were a total of 122 patients (12% of sample) with low glucoamylase values. Thirteen (1.3%) had isolated glucoamylase deficiency. There were 109 total patients with coexistent glucoamylase and other disaccharidase deficiencies. The frequency and pattern of glucoamylase deficiencies was identical to that of sucrase (p = 0.98). There is a strong correlation between glucoamylase and sucrase activities (R-SQ= 80%, P< 0.0001). The ratio of glucoamylase to sucrase activities produced a single peak of 1.2 ± 0.5. Isolated glucoamylase deficiencies were identified when this ratio was < 0.7. Conclusions: The frequencies and types of glucoamylase and sucrase deficiencies suggest that there is as much clinical value for measuring glucoamylase as for sucrase activity in mucosal biopsy assays. The 89% frequency of coexistent glucoamylase with other disaccharidase deficiencies suggests that shared regulatory factors modulate the activities of these key carbohydrate digesting small intestinal brush border enzymes.