– Ethyl-d5-malonic Acid is a deuterated compound of Ethyl-malonic Acid. Ethyl-malonic Acid has a CAS number of 601-75-2. Ethylmalonic acid can be found in blood, cerebrospinal fluid (CSF), and urine, as well as in human fibroblasts, prostate, and skeletal muscle tissues. Moreover, ethylmalonic acid is found to be associated with anorexia nervosa and malonyl-CoA decarboxylase deficiency. Ethylmalonic acid is a non-carcinogenic potentially toxic compound. Chronically high levels of ethylmalonic acid are associated with at least two inborn errors of metabolism, including short chain acyl CoA dehydrogenase deficiency (SCAD deficiency) and ethylmalonic encephalopathy.