Ornithine carbamoyl phosphate deficiency

Ornithine Transcarbamylase Deficiency (OTC Deficiency) is a genetic disorder that affects the body's ability to eliminate ammonia, a toxic byproduct of protein metabolism. This condition is part of a group of disorders known as urea cycle disorders, which cause ammonia to accumulate in the blood, leading to various health issues, including brain damage, coma, and in severe cases, death. OTC Deficiency is caused by mutations in the OTC gene, which is located on the X chromosome, making it an X-linked recessive genetic condition. This means that males are more frequently and severely affected, while females can be carriers and may or may not show symptoms of the disease.

Symptoms

Symptoms of OTC Deficiency can range from mild to severe and may include:

• Poor feeding
• Vomiting
• Lethargy
• Irritability
• Avoidance of high-protein foods
• Developmental delays
• Intellectual disability
• Seizures
• Coma

Symptoms often appear in the first few days of life in affected newborns, although less severe forms may not become apparent until later in childhood or even adulthood.

Diagnosis

Diagnosis of OTC Deficiency involves a combination of clinical evaluation, laboratory testing, and genetic testing. Blood and urine tests can detect elevated levels of ammonia and other substances indicative of a urea cycle disorder. Genetic testing can confirm a mutation in the OTC gene.

Treatment

Treatment for OTC Deficiency is aimed at reducing ammonia levels in the blood and managing symptoms. Dietary management, including restriction of protein intake and supplementation with specific amino acids, is critical. Medications such as sodium benzoate, sodium phenylbutyrate, and arginine can help to remove ammonia from the body. In severe cases, dialysis may be necessary to rapidly reduce ammonia levels. Liver transplantation may be considered in cases where medical management is not effective.

Prognosis

The prognosis for individuals with OTC Deficiency varies depending on the severity of the condition, the age at diagnosis, and the effectiveness of treatment. Early diagnosis and prompt treatment can improve the outcome significantly. However, despite treatment, some individuals may experience intellectual disability and other long-term complications.

Epidemiology

OTC Deficiency is the most common urea cycle disorder, but it is still a rare condition. It is estimated to occur in 1 in every 40,000 to 80,000 births worldwide.

See Also

• Urea cycle disorders
• Genetic disorders
• Metabolic disorders

Ornithine carbamoyl phosphate deficiency Resources
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