Glycogen branching enzyme deficiency in adult polyglucosan body disease

Branching enzyme activity was assayed in muscle, peripheral nerve, and leukocytes from 2 Ashkenazi‐Jewish patients with adult polyglucosan body disease and 1 African‐American and 3 Caucasian patients with the same clinical and pathological features. Branching enzyme activity was normal in the muscle specimens from both Jewish and non‐Jewish patients. However, the activity was markedly decreased not only in the leukocytes from the 2 Jewish patients (confirming previous findings), but also in peripheral nerve specimens, whereas it was normal in nerve tissue and leukocytes from all non‐Jewish patients. These data confirm a branching enzyme deficiency in a subgroup of patients with adult polyglucosan body disease, and show that the defect is tissue‐specific, suggesting that adult polyglucosan body disease has more than one biochemical basis. Copyright © 1993 The American Neurological Assosiation