Acute hyperammonaemic encephalopathy in a female newborn caused by a novel, de novo mutation in the ornithine transcarbamylase gene

A full-term female offspring of a first and uneventful pregnancy presented at 60 h of life with irritability, tachypnea and respiratory alkalosis progressing to deep coma with clinically dominant circulatory failure, tachycardia and hypotension. Diagnosis of ornithine transcarbamylase (OTC) deficiency was made on the basis of hyperammonaemia, hypocitrullinaemia and extreme hyper-excretion of orotic acid. The baby was treated with peritoneal dialysis, arginine hydrochloride and adequate energy supply. DNA analysis revealed an as of yet unidentified missense mutation in the 6th exon of the OTC gene, resulting in a change of lysine to glutamine at position 210 (K210Q). Her parents were not found to carry this mutation, implying that this mutation may have occurred either de novo in the patient or in a parental germ cell. Conclusion: An acute neonatal form of OTC deficiency should be considered in the differential diagnosis of coma in female newborns.