Asymptomatic Presentation of Neonatal Ornithin Transcarbamylase Deficiency: A Rare Case Report

Aim and background: Ornithine transcarbamylase deficiency (OTCD) is the most common urea cycle disorder (UCD).Neonatal presentation typically occurs mainly in hemizygous males and in females, the clinical presentation varies.We aim to highlight a case where mild neonatal respiratory distress and a strategic maternal history led to the diagnosis of familial OTCD.Case description: We report a term female neonate who presented with immediate postnatal breathlessness requiring 5 minutes of continuous positive airway pressure (CPAP).When her respiratory status improved, subsequent investigations revealed significant hyperammonemia, and an arterial blood gas (ABG) analysis revealed respiratory alkalosis.Quantitative amino acid analysis showed decreased levels of citrulline and glutamine, along with elevated histidine and glutamic acid.The mother reported a long-standing history of protein intolerance characterized by bloating and diarrhea.Initial management done with a protein-restricted formula, nitrogen scavengers (sodium benzoate), and supportive care. Conclusion:The infant stabilized and was discharged.Genetic testing subsequently confirmed a diagnosis of OTCD in both the neonate and the mother.Ornithine transcarbamylase deficiency is a rare, but potentially life-threatening inborn error of metabolism that requires a high index of clinical suspicion for early diagnosis.Clinical significance: This case highlights the importance of early metabolic screening in new-borns with unexplained hyperammonemia and also important of Genetic testing and family counseling are essential for prevention of future risk.