3-Methylglutaconic aciduria

3-Methylglutaconic aciduria is not one disease but a name for at least five distinct inherited metabolic disorders, each of which impairs the ability of the body's mitochondria to make energy. Because the affected mitochondrial pathways feed into the breakdown of the amino acid leucine, the impairment causes 3-methylglutaconic acid and the related 3-methylglutaric acid to build up in the body and become detectable in the urine, which gives the group of disorders its name. The five recognized types (I through V) each trace to different genes and follow different inheritance patterns, most autosomal recessive, one X-linked recessive, and one with an inheritance pattern that is not yet established. Symptoms vary by type but commonly include developmental delay, abnormal muscle tone, structural heart defects, recurrent infections, and vision problems, reflecting how broadly disrupted energy production can affect the developing body. The disorders are rare overall but occur more often in certain populations, including Iraqi Jews and residents of the Saguenay-Lac-Saint-Jean region of Quebec, Canada, patterns that have helped researchers trace the underlying genes. There is no known treatment or cure; management is supportive and focused on the specific complications each type produces.