GTR Home > Conditions/Phenotypes > Ornithine carbamoyltransferase deficiency

Disease characteristics

Excerpted from the GeneReview: Ornithine Transcarbamylase Deficiency
Ornithine transcarbamylase (OTC) deficiency can occur as a severe neonatal-onset disease in males (but rarely in females) and as a late-onset (partial) disease in males and females. Males with severe neonatal-onset OTC deficiency are typically normal at birth but become symptomatic from hyperammonemia on day two to three of life and are usually catastrophically ill by the time they come to medical attention. After successful treatment of neonatal hyperammonemic coma these infants can easily become hyperammonemic again despite appropriate treatment; they typically require liver transplant by age six months to improve quality of life. Males and heterozygous females with late-onset (partial) OTC deficiency can present from infancy to later childhood, adolescence, or adulthood. No matter how mild the disease, a hyperammonemic crisis can be precipitated by stressors and become a life-threatening event at any age and in any situation in life. For all individuals with OTC deficiency, typical neuropsychological complications include developmental delay, learning disabilities, intellectual disability, attention deficit hyperactivity disorder (ADHD), and executive function deficits.

Associated genes

Clinical features

  • Irritability
  • Pyloric stenosis
  • Splenomegaly
  • Protein avoidance
  • Low plasma citrulline
  • Hyperglutaminemia
  • Episodic ammonia intoxication
  • Intellectual disability
  • Stroke
  • Seizure
  • Failure to thrive
  • Vomiting
  • Lethargy
  • Coma
  • Global developmental delay
  • Hepatic failure
  • Hypoglycemia
  • Respiratory alkalosis
  • Hyperammonemia
  • Episodic ataxia
  • Cerebral edema
  • Aminoaciduria
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