D-α-Hydroxyglutaric Acid (D-2-HG) is an α-hydroxy acid that is over-produced in the human neurometabolic disease D-2-hydroxyglutaric aciduria (D-2-HGA). It is normally synthesized from 2-ketoglutarate (2-KG) by hydroxyacid-oxoacid transhydrogenase (HOT), although defects in HOT are not known to be associated with D-2-HGA. Instead, type I D-2-HGA involves mutations in D-2-hydroxyglutarate dehydrogenase, which converts D-2-HG back to 2-KG. Type II D-2-HGA results from gain-of-function mutations in isocitrate dehydrogenase 2, causing it to supplement HOT in converting 2-KG to D-2-HG. In bacteria, this α-hydroxy acid may be synthesized from oxalate and propionyl-coenzyme A by an α-hydroxyglutaric acid synthetase.
