CONCOMITANT BRANCHING ENZYME AND PHOSPHORYLASE DEFICIENCIES - AN UNUSUAL GLYCOGENOSIS WITH EXTENSIVE NEURONAL POLYGLUCOSAN STORAGE

A baby girl was born hypotonic and was respirator-dependent until deat h at 43 days of age. A muscle biopsy revealed PAS-positive, diastase-r esistant sarcoplasmic inclusions with a vaguely fibrillar structure by electron microscopy. Biochemical studies at autopsy disclosed complet e absence of branching enzyme in skeletal muscle and heart, and a defi ciency of phosphorylase activity in skeletal muscle with a modest redu ction in myocardium. Storage material was present in glia and perikary a of neurons, increasing in amount in the rostrocaudal direction, invo lving most severely the motor neurons in the brain stem and spinal cor d, dorsal root ganglia and myenteric plexi. Inclusions were also prese nt in most organs, especially liver and skeletal muscle. Ultrastructur ally, the inclusions ranged from granular aggregates of membrane-bound material concentrated in the region of Golgi apparatus to large filam entous bodies similar to polyglucosan bodies. This baby differs from o ther patients with infantile glycogenosis IV by the severity and onset of symptoms at birth, involvement of neuronal perikarya and widesprea d extraneural deposits. The combined deficiencies of branching enzyme and phosphorylase may have accounted for the unique clinical and neuro pathological findings.