Point mutation in Pompe disease in Chinese

Glycogen storage disease type II (Pompe disease) (McKusick 23230) is an autosomal recessive disorder characterized by lysosomal accumulation of glycogen (Pompe 1932; Loonen 1979). The impaired glycogen degradation is due to a deficiency of acid e-D-glucosidase (EC 3.2.1.20) (Pompe 1932; Loonen 1979). In Taiwan, Pompe disease is the most common form of glycogen storage disease (Lin et al 1987). Most cases are the infantile form (generalized glycogenosis type II). In a previous study, we generated two monoclonal antibodies (Mabs) against human acid ~-D-glucosidase to analyse the intracellular acid ~-D-glucosidase from seven Chinese Pompe disease families (Lin et al 1992). Acid e-D-glucosidase was found in the skin fibroblasts of all patients by radioimmunoprecipitation (RIP) and in the hepatic cells by immunohistological study (Lin et al 1992). However, functional assay of acid C~-D-glucosidase showed that the enzyme was defective in function in these seven patients. These findings suggest that mutation in DNA at a level that does not affect the molecular weight of acid e-D-glucosidase may be the main cause of acid C~-D-glucosidase deficiency in the Chinese Pompe disease patients. The present study was undertaken to identify the point mutation in DNA responsible for the defective function of acid ~-D-glucosidase.