The majority of those suffering from the disease are detected at birth while some only present symptoms during times of great physiological stress such as pregnancy, or with acute illnesses (viral disorders).

[11] Although it is mostly homozygotes that demonstrate symptoms of the disorder,[2] compound heterozygotes can also show clinical signs.

Without a nucleus, they lack the ability to synthesize new proteins so if anything happens to their pyruvate kinase, they are unable to generate replacement enzymes throughout the rest of their life cycle.

Without mitochondria, erythrocytes are heavily dependent on the anaerobic generation of ATP during glycolysis for nearly all of their energy requirements.

For the most part when dealing with pyruvate kinase deficiency, these two diagnostic techniques are complementary to each other as they both contain their own flaws.

Direct enzyme assays can diagnose the disorder and molecular testing confirms the diagnosis or vice versa.

With these severe cases of pyruvate kinase deficiency in red blood cells, treatment is the only option, there is no cure.

It increases the erythrocyte production (reticulocytosis) because reticulocytes are immature red blood cells that still contain mitochondria and so can produce ATP via oxidative phosphorylation.

The prevalence of pyruvate kinase deficiency is around 51 cases per million in the population (via gene frequency).

[12][19] In addition to humans, several other animals are known to be susceptible to pyruvate kinase deficiency, including dogs and cats.