 Excess amounts of these compounds can be detected in urine.It remains unclear how a loss of the ETHE1 enzyme leads to progressive brain dysfunction and the other features of ethylmalonic encephalopathy.Ethylmalonic encephalopathy is an autosomal recessive disorder, which means the defective gene is located on an autosome, and both parents must carry one copy of the defective gene in order to have a child born with the disorder.