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GTR Home > Conditions/Phenotypes > Ethylmalonic encephalopathy


Excerpted from the GeneReview: Ethylmalonic Encephalopathy
Ethylmalonic encephalopathy (EE) is a severe, early-onset, progressive disorder characterized by developmental delay / mild-to-severe intellectual disability; generalized infantile hypotonia that evolves into hypertonia, spasticity, and (in some instances) dystonia; generalized tonic-clonic seizures; and generalized microvascular damage (diffuse and spontaneous relapsing petechial purpura, hemorrhagic suffusions of mucosal surfaces, and chronic hemorrhagic diarrhea). Infants sometimes have frequent vomiting and loss of social interaction. Speech is delayed and in some instances absent. Swallowing difficulties and failure to thrive are common. Children may be unable to walk without support and may be wheelchair bound. Neurologic deterioration accelerates following intercurrent infectious illness, and the majority of children die in the first decade.

Genes See tests for all associated and related genes

  • Also known as: HSCO, YF13H12, ETHE1
    Summary: ETHE1 persulfide dioxygenase

Clinical features


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Practice guidelines

  • ACMG ACT, 2022
    American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Elevated C4 and C5 +/- Other Acylcarnitines, Glutaric Acidemia II (GA-II) (MADD), 2022
  • ACMG Algorithm,
    American College of Medical Genetics and Genomics, Algorithm, Glutaric Acidemia II (GA-II)/ MADD, Riboflavin Metabolism Disorder, Ethylmalonic Encephalopathy: C4 and C5 elevated +/- other elevated acylcarnitines (AC), 2022
  • ACMG ACT, 2022
    American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Elevated C4 Acylcarnitine, Short-Chain Acyl-CoA Dehydrogenase (SCAD) Deficiency, 2022

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