Malonic aciduria


Malonic Aciduria is a rare disorder caused by deficiency of Malonyl-CoA Decarboxylase (MCD). MCD is an enzyme that catalyzes the degradation of malonyl-CoA. Malonyl-CoA is a substrate for fatty acid synthesis and it also regulates oxidation of fatty acids by controlling their uptake into mitochondria. MCD may therefore regulate fatty acid synthesis and oxidation by affecting intracellular malonyl-CoA levels, but its function is not completely known. The gene for MCD, located on chromosome 16, has been cloned and mutations identified in patients with MCD deficiency.


* Developmental delay * Poor muscle tone * Seizures * Diarrhea * Vomiting


There is limited experience in managing this rare disorder. Dietary modification to increase the amount of calories from carbohydrate relative to fat has been effective in improving metabolic abnormalities. Extended fasting should be avoided. Carnitine supplementation has been beneficial in some patients. Because the diagnosis and therapy of Malonic Aciduria is complex, the pediatrician is advised to manage the patient in close collaboration with a consulting pediatric metabolic disease specialist. It is recommended that parents travel with a letter of treatment guidelines from the patient’s physician.