Biochemical characterization of human D-2-hydroxyglutarate dehydrogenase and two disease related variants reveals the molecular cause of D-2-hydroxyglutaric aciduria.
We report a set of 412-year-old monozygotic (MZ) female twins with D-2-hydroxyglutaric aciduria who are shown to be compound heterozygotes for c.326-327dupTC, p.Glu110ArgfsX19, and c.1123G-->T, p.Asp375Tyr mutations in the D-2-hydroxyglutarate dehydrogenase gene, but who have remarkably different clinical phenotypes.
Overexpression studies in HEK-293 cells of proteins containing the missense mutations showed a marked reduction of d-2-hydroxyglutarate dehydrogenase activity, proving that mutations in the d-2-hydroxyglutarate dehydrogenase gene cause d-2-hydroxyglutaric aciduria.
Recently, we reported pathogenic mutations in the D-2-hydroxyglutarate dehydrogenase gene as the cause of the severe phenotype of D-2-hydroxyglutaric aciduria in two patients.
In one D-2HGA case we identified mosaicism for an IDH2 mutation as the genetic cause of this disorder; the other D-2HGA case was caused by a heterozygous IDH2 mutation, while the unaffected mother was a mosaic carrier.
We have detected heterozygous germline mutations in IDH2 that alter enzyme residue Arg(140) in 15 unrelated patients with d-2-hydroxyglutaric aciduria (D-2-HGA), a rare neurometabolic disorder characterized by supraphysiological levels of D-2-HG.
A report in the current issue of Science describes a germline IDH2 mutation in a subset of patients with a rare metabolic disorder--D-2-hydroxyglutaric aciduria-that is similar to mutations seen in cancer patients.
Overexpression studies in HEK-293 cells of proteins containing the missense mutations showed a marked reduction of d-2-hydroxyglutarate dehydrogenase activity, proving that mutations in the d-2-hydroxyglutarate dehydrogenase gene cause d-2-hydroxyglutaric aciduria.