title: A case of McArdle disease: efficacy of vitamin B6 on fatigability and impaired glycogenolysis.
abstract: McArdle disease is a glycogenetic myopathy caused by a deficit of myophosphorylase inherited in an autosomal recessive pattern. Here, we report a case of McArdle disease in which fatigability was the only subjective complaint. Objective neurological findings were normal except for very mild muscle weakness in limbs and an elevated serum creatine kinase level. Ischemic forearm exercise test showed deficient glycogenolysis. In the muscle biopsy specimen, periodic acid Schiff (PAS) stained subsarcolemmal glycogen was increased and the muscle phosphorylase A activity was decreased. After administration of vitamin B6, fatigability was diminished and ischemic forearm exercise test showed improved glycogenolysis. Vitamin B6 may be beneficial for McArdle disease, especially for its easy fatigability.
authors.affiliation: Department of Neurology, Tohoku University School of Medicine, Sendai.
authors.forename: Rumiko
authors.initials: R
authors.lastname: Izumi
authors.forename: Naoki
authors.initials: N
authors.lastname: Suzuki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kato
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Warita
authors.forename: Maki
authors.initials: M
authors.lastname: Tateyama
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nakashima
authors.forename: Yasuto
authors.initials: Y
authors.lastname: Itoyama
mesh_terms: D005221:Fatigue / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D005260:Female; D006012:Glycogen Storage Disease Type V / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D050261:Glycogenolysis / Q000187:drug effects*; D006801:Humans; D016896:Treatment Outcome; D025101:Vitamin B 6 / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D025101:Vitamin B 6