PFKM and glycogen storage disease VII: Autosomal-recessive mutations in the PFKM gene (OMIM #610681) cause GSD type VII, or Tarui’s disease, a metabolic myopathy characterized by phosphofructokinase (PFK) deficiency resulting in impaired conversion of fructose-6-phosphate to fructose-1.6-diphosphate, affecting both anaerobic and aerobic glycolysis.