Mutations in TIMM50 lead to the clinical phenotype of 3-methylglutaconic aciduria type IX (MGCA9), an autosomal recessive disorder characterized by developmental delay, seizures, hypotonia and increased levels of 3-MGC, similar to DCMA and other 3-methylglutaconic acidurias, including type VII (MGCA7) and VIII (MGCA8), which will be discussed later [61,80,81]. The gene discussed is HTRA2; the disease is 3-methylglutaconic aciduria type 9.