Summary
L2-hydroxyglutaricaciduria (L-2-HGA) is characterized by the significant elevation of plasmatic and urinary levels of L2- hydroxyglutaric acid. L2- hydroxyglutaric acid is measured by gas chromatography of organic acids. L-2-HGA occurs in children aged 2 years, causing moderate psychomotor retardation, progressive ataxia, extrapyramidal signs, followed by progressive decline of IQ. The MRI shows a spongiform encephalopathy and cerebellar atrophy. There is no specific treatment for this disease. Prenatal diagnosis can be made by analysing organic acids in amniotic fluid. The gene responsible for L-2-HGA has been identified recently; it is localised on chromosome 14q22.1. It has been proposed to name it duranin. This gene encodes a putative mitochondrial protein with homology to FAD-dependent oxidoreductases. D2-hydroxyglutaricaciduria (D-2-HGA) has also been observed in patients with intellectual deficit exhibiting various neurological signs, although there was no real regression. The enzyme deficiency remains to be discovered. Recently, a severe neonatal form of hydroxyglutaric aciduria has been described, but the underlying enzymatic defect remains unknown. Rare cases of both D-2 and L-2 glutaric aciduria have been reported. Antenatal diagnosis, although difficult, is feasible by enzymatic assay in amniotic fluid.*Author: Pr. J-M. Saudubray (February 2005)*.
