3-Methylglutaconic aciduria type I causes leukoencephalopathy of adult onset

3-Methylglutaconic amino aciduria (MGA) is characterized by an increased urinary excretion of 3-methylclutaconic acid and 3-methylglutaric acid.1 Four distinct forms are currently recognized: type I (MGA1), 3-methylglutaconyl-CoA hydratase deficiency caused by mutations of the AUH gene1–7; type II, caused by mutations in the tafazzin gene; type III, occurring in a genetic isolate of Iraqi Jews (causative gene has been recently isolated); and type IV, a heterogeneous group. The symptoms usually appear in the first decade of life.1–7 We herein report MGA1 presenting with progressive leukoencephalopathy in late adulthood. A 55–year-old woman was referred to us for an evaluation of progressive forgetfulness and an unsteady gait since age 53. Urinary incontinence also appeared at age 52. She easily tripped and fell, resulting in a fracture of her right clavicle. Her parents were first cousins. She had no serious illnesses during her childhood, graduated from a junior college, got married at age 23, and gave birth to two healthy children. …