Muscle phosphorylase b kinase deficiency revisited

Neuromuscul Disord. 2010 Feb;20(2):125-7. doi: 10.1016/j.nmd.2009.11.004. Epub 2010 Jan 18.

Abstract

Muscle phosphorylase b kinase (PHK) deficiency (glycogenosis type VIII) is a rare disorder caused by mutations in the PHKA1 gene encoding the alpha(M) subunit of PHK. Only 5 patients with molecular defects in the X-linked PHKA1 gene have been described until now, and they all presented with exercise intolerance. Here, we report a patient with a new mutation in the PHKA1 gene who presented with PHK deficiency, cognitive impairment, but no overt myopathy. This report supports the concept that PHK deficiency is a mild metabolic myopathy and suggests that PHK mutations may interfere with normal brain function.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Amino Acid Sequence / genetics
  • Biopsy
  • Brain / enzymology
  • Brain / physiopathology
  • Codon, Nonsense / genetics
  • Cognition Disorders / enzymology*
  • Cognition Disorders / genetics*
  • Cognition Disorders / physiopathology
  • Creatine Kinase / blood
  • DNA Mutational Analysis
  • Electromyography
  • Exercise Tolerance / genetics
  • Glycogen Storage Disease Type V / complications
  • Glycogen Storage Disease Type V / enzymology*
  • Glycogen Storage Disease Type V / genetics*
  • Humans
  • Intellectual Disability / enzymology
  • Intellectual Disability / genetics
  • Intellectual Disability / physiopathology
  • Intelligence / genetics
  • Male
  • Muscle Weakness / enzymology
  • Muscle Weakness / genetics
  • Muscle, Skeletal / enzymology
  • Muscle, Skeletal / physiopathology
  • Phosphorylase Kinase / deficiency*
  • Phosphorylase Kinase / genetics*
  • Protein Subunits / genetics
  • Protein Subunits / metabolism

Substances

  • Codon, Nonsense
  • Protein Subunits
  • Phosphorylase Kinase
  • Creatine Kinase