title: Adult phosphorylase b kinase deficiency.
abstract: Phosphorylase b kinase deficiency affecting muscle has been observed infrequently in children with weakness and hepatomegaly, and in 2 adults with cramps on exertion. We observed 2 additional adults with phosphorylase b kinase deficiency: Patient 1, aged 58, had progressive, predominantly distal weakness since age 46 but no cramps on exertion; Patient 2, aged 26, had cramps on exertion since age 6 but no weakness. Lactate production on ischemic exercise was impaired only in Patient 1. The serum creatine kinase level was elevated in both. Muscle specimens showed focal glycogen excess in both, and a necrotizing myopathy and mild denervation atrophy in Patient 1. Muscle phosphorylase b kinase activity was 0.5% and 8.9% of the lowest control value in Patients 1 and 2, respectively; erythrocyte phosphorylase b kinase activity was normal in both; liver phosphorylase b kinase activity, measured in Patient 1, was also normal. Other glycolytic enzymes in muscle were preserved in both.
authors: Department of Neurology, Mayo Clinic, Rochester, MN 55905.
authors: P R
authors: PR
authors: Clemens
authors: M
authors: M
authors: Yamamoto
authors: A G
authors: AG
authors: Engel
mesh_terms: D000328:Adult; D003402:Creatine Kinase / Q000097:blood; D006003:Glycogen / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009120:Muscle Cramp / Q000209:etiology*; D009124:Muscle Proteins / Q000172:deficiency* / Q000378:metabolism; D009132:Muscles / Q000201:enzymology* / Q000473:pathology; D009133:Muscular Atrophy / Q000209:etiology; D010764:Phosphorylase Kinase / Q000172:deficiency* / Q000235:genetics; D005082:Physical Exertion; D013577:Syndrome; D014960:X Chromosome
chemical_list: D009124:Muscle Proteins; D006003:Glycogen; D010764:Phosphorylase Kinase; D003402:Creatine Kinase