Regarding the relative frequency of organic acidemias in our population, aninteresting observation was the high number of glutaric aciduria type I (59patients) and 3-hydroxy-3-methylglutaric aciduria (40 patients) detected in ourstudy, with a similar prevalence to the other most prevalent organic acidurias, suchas methylmalonic acidemia (due to mutase deficiency or various cobalamindeficiencies including CblC and Cbl A). The gene discussed is CBLC; the disease is methylmalonic acidemia.