Mutation in several genes can lead to different types of 2-hydroxyglutaric aciduria. For example, the D2HGDH and L2HGDH genes provide instructions for making enzymes that are found in mitochondria - in which these enzymes break down D-2-hydroxyglutarate and L-2-hydroxyglutarate, respectively, as a part of normal reaction series that generate energy for cell activities. Any mutations occur in either of these genes would interrupt the functional enzymes and allow both 2-hydroxyglutarates to accumulate in cells, which cause 2-hydroxyglutaric aciduria type I. Moreover, it is known that type II for L-2-hydroxyglutaric aciduria and a mixed type for both 2-hydroxyglutarates come from mutations in IDH2 gene and SLC25A1 gene, respectively.[3][4]
Diagnosis
Classification
2-hydroxyglutaric aciduria is an organic aciduria, and because of the stereoisomeric property of 2-hydroxyglutarate different variants of this disorder are distinguished:
It is associated with L2HGDH, which encodes L-2-hydroxyglutarate dehydrogenase.[6] L-2-hydroxyglutarate is produced by promiscuous action of malate dehydrogenase on 2-oxoglutarate, and L-2-hydroxyglutarate dehydrogenase is an example of a metabolite repair enzyme that oxidizes L-2-hydroxyglutarate back to 2-oxoglutarate.[7]
The combined form is characterized by severe early-onset epileptic encephalopathy and absence of developmental progress.[11] It is caused by recessive mutations in SLC25A1 encoding the mitochondrial citrate carrier.[12]
Treatment
The treatment of 2-Hydroxyglutaric aciduria is based on seizure control, the prognosis depends on how severe the condition is.[13]
^Muntau A, Röschinger W, Merkenschlager A, van der Knaap MS, et al. (2000). "Combined D-2- and L-2-hydroxyglutaric aciduria with neonatal onset encephalopathy: a third biochemical variant of 2-hydroxyglutaric aciduria?". Neuropediatrics. 31 (3): 137–40. doi:10.1055/s-2000-7497. PMID10963100.