Adult phosphorylase b kinase deficiency

Paula R. Clemens, Masahiko Yamamoto, Andrew G. Engel

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)529-538
Number of pages10
JournalAnnals of neurology
Issue number4
StatePublished - Oct 1990

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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