CoQ10  Deficiency Is Not a Common Finding in GLUT1 Deficiency Syndrome
CoQ10 deficiency has been recently described in tissues of a patient with GLUT1 deficiency syndrome. Here, we investigated patients and mice with GLUT1 deficiency in order to determine whether low CoQ is a recurrent biochemical feature of this disorder, to justify CoQ10 supplementation as therapeutic option.CoQ10 levels were investigated in plasma, white blood cells, and skin fibroblasts of 16 patients and healthy controls and in the brain, cerebellum, liver, kidney, muscle, and plasma of 4-month-old GLUT1 mutant and control mice.CoQ10 levels in plasma did not show any difference compared with controls. Since most of the patients studied were on a ketogenic diet, which can alter CoQ10 content in plasma, we also analyzed white blood cells and cultured skin fibroblasts. Again, we found no differences. In mice, we found slightly reduced CoQ in the cerebellum, likely an epiphenomenon, and activity of the mitochondrial respiratory chain enzymes was normal.Our data from GLUT1 deficiency patients and from GLUT1 model mice fail to support CoQ10 deficiency as a common finding in GLUT1 deficiency, suggesting that CoQ deficiency is not a direct biochemical consequence of defective glucose transport caused by molecular defects in the SLC2A1 gene.