title: Adult-onset exercise intolerance due to phosphorylase b kinase deficiency.
abstract: Muscle-specific phosphorylase b kinase deficiency is an unusual form of glycogen storage disorder. The majority of patients are male with an age at diagnosis between 15 to 36 years. Clinical features include exercise intolerance, myalgia and muscle weakness. A forearm ischaemic exercise test is usually normal and histochemical staining for myophosphorylase positive. The demonstration of reduced muscle phosphorylase b kinase activity by biochemical assay confirms the diagnosis. We report a 36 year old male with phosphorylase b kinase deficiency and symptom onset in adult life.
authors.affiliation: Department of Neurology, Bankstown-Lidcombe Hospital, Bankstown, NSW 2200, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Bak
authors.forename: D
authors.initials: D
authors.lastname: Cordato
authors.forename: W F
authors.initials: WF
authors.lastname: Carey
authors.forename: D
authors.initials: D
authors.lastname: Milder
mesh_terms: D000328:Adult; D017668:Age of Onset; D017079:Exercise Tolerance; D006012:Glycogen Storage Disease Type V / Q000175:diagnosis* / Q000378:metabolism*; D006801:Humans; D008297:Male; D010764:Phosphorylase Kinase / Q000172:deficiency*
chemical_list: D010764:Phosphorylase Kinase