Glycogenosis type 2


Glycogenosis type 2: A rare inherited biochemical disorder involving the harmful accumulation of certain chemicals (glycogen) in body tissues due to the deficiency of an enzyme (?-glucosidase or acid maltase) needed to break it down. The severity of the condition is variable and onset may occur during infancy, childhood or adulthood.


The list of signs and symptoms mentioned in various sources for Glycogenosis type 2 includes the 25 symptoms listed below: * Reduced muscle tone * Enlarged heart * Difficulty swallowing * Failure to thrive * Enlarged liver * Progressive muscle weakness * Failure to achieve milestones for motor development * Overly relaxed facial muscles * Enlarged tongue * Lack of reflexes * Recurrent respiratory infections * Abnormal gait * Gower sign * Exercise intolerance * Scoliosis * Lordosis * Kyphosis * Lower back pain * Decreased deep tendon reflexes * Sleep apnea * Somnolence * Shortness of breath on exertion * Thickening of heart muscle * Mental retardation * Glycogen deposits in the heart


The diagnosis of glycogenosis type II is often complicated by the rarity of the condition and the heterogeneity of the clinical manifestations of the disease. It is a progressive, debilitating, and often fatal neuromuscular disorder that manifests as a continuum of clinical phenotypes, which vary with respect to organ involvement, age at onset, and severity. Early diagnosis requires both increased awareness among physicians regarding the clinical characteristics of the disease and fast and reliable acid alpha-glucosidase (GAA) enzyme activity assays to confirm the GAA deficiency. The clinical diagnosis of glycogenosis type II is confirmed by virtual absence (found in infants) and marked reduced activity (found in juveniles and adults) of GAA enzyme in blood samples, cultured fibroblasts, and muscle biopsies. This article specifically highlights the need for early recognition of the clinical manifestation of the disease in infants, juveniles, and adults. Descriptions of the main clinical features of the condition, as well as differential diagnosis are included. In addition, the tests required for a confirmed diagnosis are described, and use of muscle imaging to evaluate muscle pathology is reviewed.