Molecular genetic heterogeneity of phosphoglycerate kinase (PGK) deficiency

Phosphoglycerate kinase (PGK; EC 2.7.2.3) is a glycolytic enzyme encoded by a single gene on the X chromosome and ubiquitously expressed. Hereditary PGK deficiency can cause hemolytic anemia, central nervous system dysfunction, and/or myopathy characterized by exercise intolerance, cramps, and myoglobinuria. So far, 20 PGK variants with reduced PGK activity have been identified, 8 of them in patients with myopathy. Six missense mutations and one splice-junction mutation have been identified in 7 patients, 2 of whom had myopathy. However, the biochemical and molecular bases for clinical heterogeneity in PGK deficiency remain unknown.