OTC Deficiency: Cause & Cure for Ornithine Transcarbamylase Deficiency

OTC deficiency is ornithine transcarbamylase deficiency; it is disorder of urea cycle. OTC is a rare metabolic disorder genetic in origin, where there is deficiency of one of the enzymes occurring in the urea cycle.

There is a series of steps in the urea cycle which takes place in the liver. Here the nitrogen which is generated while metabolizing protein is converted into urea.

Urea cycle passes through five steps, and each step requires a specific enzyme. During this cycle, if one enzyme is missing, there is accumulation of nitrogen in the blood, which gets converted into ammonia instead of urea.

Excess of ammonia is a toxic; especially it damages the brain and central nervous system. OTC deficiency causes this problem.

Symptoms of OTC Deficiency

The symptoms occur due to accumulation of ammonia in the blood, which the body is unable to get rid off.

OTC deficiency occurs in the first few days after the birth, some time it can occur in the middle age, especially in women.

The Infant may be

  • Lethargic.
  • Low respiratory rate.
  • Refusal to eat.
  • Some may show hyperactive behavior.
  • Crying and screaming.
  • Vomiting.
  • Seizures
  • Delirium
  • Coma.

When OTC enzyme production is totally absent, the child may survive only for few days.

Complication of Ornithine Transcarbamylase Deficiency

  • Delayed growth development.
  • Mental retardation.
  • Liver damage.
  • Brittle hair.
  • Eczema.
  • Poor performance in the school.

In Persons where the Symptoms are Less Severe

  • Occur later in life.
  • Female becomes affected, due to metabolic stress.
  • It can happen due to pregnancy, malnourishment, and gastric bypass.


  • Low protein diet, as the disease is unable to handle large amount of nitrogen.
  • In acute illness, care should be taken to keep body well hydrated.
  • Use of medications to remove ammonia from the blood.
  • Supplemental amino acids.
  • Liver transplant in extreme cases.


  • Females are carriers as X chromosome linked recessive disorder.
  • Males do not survive for more than 3 days after the birth in OTC deficiency; half survives for a month and other die within 5 years.
  • Prognosis is not clear in adults.