Enzymes of Glycogen Metabolism in Human Skin with Particular Reference to Differential Diagnosis of the Glycogen Storage Diseases

Abstract

1. A vacuum skin-blistering technique has been successfully applied and the human epidermal tissue so obtained has been examined for glycogen content and some of the enzymes involved in glycogen metabolism. 2. Normal values for glycogen phosphorylase, acid α-glucosidase and amylo-1,6-glucosidase (debranching enzyme) in epidermis are reported. Glucose 6-phosphatase activity was not detected. 3. Examination of two patients with Type II glycogen storage disease (Pompe's Disease—lack of lysosomal acid α-glucosidase) revealed an absence of the acid α-glucosidase in their skin. 4. The enzymic lesion in Type V glycogen storage disease (McArdle's Disease—lack of muscle phosphorylase) was not reflected in the epidermal tissue of a patient and a normal level of the enzyme was observed.

McArdle disease: The mystery of reappearing phosphorylase activity in muscle culture—A fetal isoenzyme

“…I n other tissues, however, enzymatic activity is present. This has been directly tested in leukocytes [ 191, platelets [2, 121, skin [14], and cultured skin fibroblasts [8, 91…”

“…I n other tissues, however, enzymatic activity is present. This has been directly tested in leukocytes [ 191, platelets [2, 121, skin [14], and cultured skin fibroblasts [8, 91 and has been inferred from the lack of clinical disorders of heart, liver, kidney, or brain. Restriction of the genetic enzyme defect to muscle suggests that normally the enzyme proteins in other tissues are under separate genetic control and have different primary structure; they are isoenzymes.…”

Glycogen Storage Diseases

“…However, on examination of platelet phosphorylase from a McArdle patient and his family, there appeared to be no diminution of the level of activity compared with normal (Ryman and Chung, 1969). Phosphorylase activity is not lost from the skin in type V (Leathwood and Ryman, 1971) or from cultured fibroblasts (Dreyfus and Alexandre, 1971).…”

“…Diagnosis of type II disease is achieved by direct assay of tissue such as liver, muscle, or skin (Leathwood and Ryman, 1971). Cultured fibroblasts (see Brown and Brown, 1972; and DiMauro, Rowland, and Mellman, 1973) appear to be suitable for enzyme analysis, and furthermore show an accumulation of glycogen in vacuoles (Hug, Schubert, and Soukup, 1971).…”