ETHE1 and ethylmalonic encephalopathy: In addition, ethylmalonic encephalopathy, an autosomal recessive disease which is associated with neurological impairment is, at least in part, due to the excessive accumulation of H2S; in this instance this is caused by ETHE1 mutations, which decrease the clearance of H2S due to the downregulation of mitochondrial sulfur dioxygenase [55].