The most common urea cycle disorder, an X-linked condition causing inability to eliminate ammonia. Ammonia accumulates causing neurotoxicity. Can present in neonates (severe) or later (variable). Hemizygous males more severely affected.

• 1Genetic testing
• 2Clinical evaluation
• 3Family history assessment
• 4Specialized laboratory tests
• 5Imaging studies
• 6Biopsy (if applicable)

Variable. Severe neonatal onset has high mortality. Late-onset manageable with protein restriction and ammonia scavengers. Liver transplant curative.

• Genetic counseling
• Carrier screening
• Prenatal diagnosis
• Preimplantation genetic diagnosis
• Family planning