3-methylglutaconic aciduria type 5 (MONDO_0012435, a Monarch Disease Ontology term) is a syndrome characterized by severe early onset (before the age of three years) dilated cardiomyopathy (DCM) with conduction defects (long QT syndrome), non-progressive cerebellar ataxia, testicular dysgenesis, and 3-methylglutaconic aciduria. Also known as: 3-methylglutaconic aciduria caused by mutation in DNAJC19, 3-methylglutaconic aciduria type V, DCMA, DCMA syndrome, DNAJC19 3-methylglutaconic aciduria, MGA5, MGCA5, dilated cardiomyopathy with ataxia.