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Adult phosphorylase b kinase deficiency
Author(s) -
Clemens Paula R.,
Yamamoto Masahiko,
Engel Andrew G.
Publication year - 1990
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410280410
Subject(s) - phosphorylase kinase , medicine , glycogen phosphorylase , exertion , creatine kinase , myoglobinuria , endocrinology , myopathy , weakness , muscle cramp , muscle weakness , glycogen , surgery , rhabdomyolysis
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.