Biopsy-proven alpha-glucosidase deficiency with normal lymphocyte enzyme activity.
Alpha-glucosidase deficiency is a rare cause of muscle disease in adults. The diagnosis relies on recognition of the salient clinical features and determination of significantly reduced alpha-glucosidase (GAA) activity. Lymphocytes are the usual tissue for diagnostic enzymology; discrepant results from analyses of different tissues are unusual. We report a patient with clinical, electromyographic, and biopsy findings indicative of alpha-glucosidase deficiency whose muscle and lymphocyte enzyme results were markedly discrepant on multiple analyses. As a result, we conclude that all patients with suspected alpha-glucosidase deficiency and a normal lymphocyte GAA assay should also have a determination of GAA activity in muscle or skin fibroblasts.
Whitaker
Charles H
CH
Department of Neurology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, Connecticut 06030, USA. cwhitaker@nso.uchc.edu
Felice
Kevin J
KJ
Natowicz
Marvin
M
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D001706:Biopsy; D004576:Electromyography; D005087:Glucan 1,4-alpha-Glucosidase / Q000172:deficiency* / Q000378:metabolism; D006009:Glycogen Storage Disease Type II / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008214:Lymphocytes / Q000201:enzymology; D008297:Male; D008854:Microscopy, Electron; D018485:Muscle Fibers, Skeletal / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D018908:Muscle Weakness / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D000520:alpha-Glucosidases
D000520:alpha-Glucosidases; D005087:Glucan 1,4-alpha-Glucosidase