Nitric oxide synthesis in ornithine transcarbamylase deficiency: possible involvement of low no synthesis in clinical manifestations of urea cycle defect.

Nitric oxide (NO) levels in plasma and urine were determined in 5 girls with ornithine transcarbamylase deficiency (OTCD) of late-onset type, who often developed migraine-like headache or vomiting. The patients were found to have low NO synthesis, suggesting that the low NO synthesis contributes to the clinical manifestations of urea cycle defect.