Ornithine transcarbamylase deficiency

Ornithine transcarbamylase deficiency
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Hyperammonemia, lethargy, vomiting, seizures
Complications	N/A
Onset	Neonatal or later in life
Duration	N/A
Types	N/A
Causes	Genetic mutation in the OTC gene
Risks	N/A
Diagnosis	Genetic testing, ammonia levels
Differential diagnosis	N/A
Prevention	N/A
Treatment	Low-protein diet, ammonia scavenging drugs, liver transplant
Medication	N/A
Prognosis	Variable, depending on severity and treatment
Frequency	N/A
Deaths	N/A

Ornithine transcarbamylase deficiency (OTC deficiency) is a rare genetic disorder that affects the urea cycle, a series of biochemical reactions that occur in the liver to remove ammonia from the bloodstream. It is the most common urea cycle disorder and is inherited in an X-linked recessive pattern.

Signs and Symptoms

Individuals with OTC deficiency may present with symptoms of hyperammonemia, which can include lethargy, vomiting, seizures, and coma. In severe cases, especially in neonates, it can lead to brain damage or death if not treated promptly. Milder forms may present later in life with episodes of confusion, headache, and behavioral changes.

Genetics

OTC deficiency is caused by mutations in the OTC gene, which provides instructions for making the enzyme ornithine transcarbamylase. This enzyme is critical for the proper function of the urea cycle. Mutations in the OTC gene lead to a deficiency or absence of the enzyme, resulting in the accumulation of ammonia in the blood.

Diagnosis

Diagnosis of OTC deficiency is based on clinical symptoms, elevated ammonia levels in the blood, and confirmation through genetic testing. Newborn screening may detect elevated levels of certain metabolites that suggest a urea cycle disorder.

Treatment

Management of OTC deficiency involves reducing ammonia levels in the blood. This can be achieved through a low-protein diet, the use of ammonia scavenging drugs such as sodium phenylbutyrate or sodium benzoate, and in some cases, liver transplant. Early diagnosis and treatment are crucial to prevent neurological damage.

Prognosis

The prognosis for individuals with OTC deficiency varies depending on the severity of the enzyme deficiency and the timeliness of treatment. With appropriate management, individuals can lead relatively normal lives, although they may need to adhere to dietary restrictions and medication regimens.

See Also

• Urea cycle disorder
• Hyperammonemia
• Genetic disorder

External Links

• National Organization for Rare Disorders
• Genetic and Rare Diseases Information Center