Clinical research of two cases of late-onset ornithine carbamoyltransferase deficiency / 中华神经科杂志

ABSTRACT

Objective To explore the clinical characteristics of late-onset ornithine carbamoyltransferase deficiency (OTCD) in order to improve the clinicians' understanding of this disease.Methods The clinical,therapeutic and follow-up data of two patients with late-onset OTCD diagnosed in the Department of Neurology,Qilu Hospital of Shandong University from November 2017 to February 2018 were collected and analyzed.Results Case 1 is a 17-year-old male who was admitted into Qilu Hospital with recurrent dizziness and vomiting for 4 months,sudden mental abnormality and convulsion for 3 days.The liver dysfunction,respiratory alkalosis and hyperammonemia (434 μmol/L) had been found before his admission.His blood ammonia fluctuated obviously from 180 μ mol/L to 2998 μmol/L,though he was given hemodialysis and arginine infusion,and died on the fourth day after admission.Case 2 is a 15-year-old male,complained with recurrent dizziness,vomiting,bluntness and somnolence for 20 days.He was found with hyperammonemia (600 μmol/L) and liver dsyfunction in a local hospital.He was getting better after intravenous administration of arginine and liver protective drugs.After admission,the blood ammonia,liver function and amino acids,acylcarnitine profiling in dried blood spots,and organic acid analysis in urine were normal,and he has not recurred since restriction of protein diet.Brain magnetic resonane imaging of both patients showed cytotoxic edema of bilateral frontal lobe and insular cortex,and their genetic detection both showed c.119G＞A(p.R40H) hemizygous pathogenic mutation of OTC gene inherited from their respective mothers.Conclusion Unexplained hyperammonemia and acute encephalopathy with insular and frontal cortical involvement should be on the alert to the urea cycle disorders,especially OTCD.Early diagnosis and reasonable treatment are the key to changing the prognosis.