A Technique for the Enzymatic Diagnosis of Glycogen Storage Disease on Very Small Tissue Specimens

Summary The difficulties to obtain an exact diagnosis in cases of glycogen storage disease are mentioned. New diagnostic methods, utilizing blood cells, have not allowed settling a definite diagnosis in all cases. Analyses on liver tissue, consequently, are still needed in many cases. However, the methods up to now used for obtaining a piece of liver tissue (surgery or large‐diameter needle‐biopsy) involve dangers to the patient. Because of this, a less risky biopsy procedure, such as can be performed with a fine‐needle, was thought preferable. To be able to utilize very small amounts of liver tissue, as obtainable with a fine‐needle, for the diagnosis of glycogen storage disease, methods were worked out, allowing the analysis of glucose‐6‐phosphatase, phosphorylase, amylo‐1,6‐glucosidase, α‐glucosidase, glycogen and protein on 0.5‐2 mg fragments of liver tissue. The metnods involved incubation of very small volumes, assay of phosphorus by a newly described, highly sensitive method and of glucose by the hexokinase‐glucose‐6‐phosphate dehydrogenase method with fluorimetric measurement of the NADPH. Protein and glycogen could be assayed in a more conventional way. The stability of the enzyme activities and the precision of the methods is discussed. Results on liver biopsy specimens from seven controls and on biopsy and autopsy specimens from liver in eight cases of four different types of glycogen storage disease are given and compared to the results on these specimens with earlier described methods.