Siblings with Ethylmalonic Encephalopathy: Case Report

Abstract

Deficiency of mitochondrial sulfur dioxygenase (ETHE1) causes a rare inborn error of metabolism, ethylmalonic encephalopathy, which is characterized by early-onset encephalopathy, chronic hemorrhagic diarrhea, recurrent petechiae, orthostatic acrocyanosis, defective cytochrome C oxidase because of hydrogen sulfide accumulation and death in the first years of life. Biochemical hallmarks of the disease are high level of lactate, C4-C5-acylcarnitines in blood and markedly elevated urinary excretion of methylsuccinic and ethylmalonic acids. We report on two siblings who were admitted to a pediatric metabolic unit with acrocyanosis, chronic diarrhea and psychomotor retardation later diagnosed as ethylmalonic encephalopathy. Molecular analyses revealed a homozygous for p.R163Q (c.488 G>A) mutation in ETHE1 gene.

Keywords

• Acrocyanosis
• developmental delay
• ETHE1
• ethylmalonic encephalopathy