Phosphofructokinase deficiency

Phosphofructokinase deficiency, also known as Glycogen storage disease type VII or Tarui's disease, is a metabolic disorder with autosomal recessive inheritance, in which deficiency of the M subunit of the phosphofructokinase enzyme impairs the ability of cells such as erythrocytes and rhabdomyocytes to use carbohydrates (such as glucose) for energy. It may affects humans as well as other mammals (especially dogs). In humans it is the least common type of glycogen storage disease.

Presentation
The disease presents with exercise-induced muscle cramps and weakness (sometimes rhabdomyolysis), as well as with hemolytic anemia causing dark urine a few hours later.