Aciduria argininosuccínica: informe de un caso de inicio neonatal / Argininosuccinic aciduria: Neonatal case report

Los defectos del ciclo de la urea son enfermedades metabólicas hereditarias que se producen por defecto en una de las enzimas encargadas de la desintoxicación del amonio, lo que genera su acumulación en el organismo. Las manifestaciones clínicas pueden presentarse en la etapa neonatal, con morbimortalidad elevada, o de forma tardía. La heterogeneidad de los síntomas y la falta de sospecha clínica en neonatos conducen a un diagnóstico erróneo y se puede confundir con sepsis neonatal o hemorragias cerebrales. El aumento de amonio plasmático en el examen bioquímico orienta su diagnóstico hacia un defecto del ciclo de la urea.La aciduria argininosuccínica es el tercer defecto más frecuente del ciclo de la urea y es causada por deficiencia de la enzima argininosuccínico liasa. Se presenta el informe de un caso de inicio neonatal. Los objetivos son enfatizar en su sospecha diagnóstica y proponer herramientas diagnósticas tempranas, como su incorporación a la pesquisa metabólica neonatal.

Urea cycle defects are inborn errors of metabolism produced by a defect in one of the enzymes responsible for the detoxification of ammonia, which generates its accumulation in the body. The clinical manifestations can present early, with high morbidity and mortality, or late onset. The heterogeneity of the symptoms and the lack of clinical suspicion in neonates leads to a wrong diagnosis, which can be confused with neonatal sepsis or cerebral hemorrhages. The increase in plasma ammonia in the biochemical examination orients his diagnosis towards a defect of the urea cycle.Argininosuccinic aciduria is the third most frequent defect of the urea cycle, and is caused by a argininosuccinate lyase deficiency. A neonatal onset case report is presented. The objective is to emphasize its diagnostic suspicion, and to propose early diagnostic tools such as its incorporation into the neonatal metabolic screening.

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

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.

Multidisciplinary perinatal management of a woman and her baby with ornithine transcarbamylase deficiency / 中华围产医学杂志

Objective To investigate the clinical features and gene mutation of a newborn with neonatal-onset ornithine transcarbamylase deficiency (OTCD) and report the multidisciplinary perinatal management of the mother with late-onset OTCD.Methods The clinical features,biochemical data and the treatment of a newborn boy with OTCD and his mother admitted by Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine in April,2013,were collected.The ornithine transcarbamylase (OTC) gene in the family was analyzed.Results Serum ammonium in the male newborn gradually increased to 1 020 μ mol/L at 48 h after birth.His blood amino acids level and urine organic acid level showed a pattern indicative of OTCD [blood arginine (97.43 μ mol/L,reference 1.00-25.00 μ mol/L),citrulline (27.43 μ mol/L,reference 4.00-30.00 μ mol/L),ornithine (161.66 μ mol/L,reference 10.00-120.00 μ mol/L) and methionine (70.45 μ mol/L,reference 10.00-50.00 μ mol/L); urine uracil (67.11 μ mol/mol Crea,reference 0.00-7.00 μ mol/mol Crea) and orotic acid (1 372.66 μ mol/mol Crea,reference 0.00-1.50 μ mol/mol Crea)].DNA studies revealed a c.583G ＞ A (G195R) homozygous mutation of the OTC gene.His mother was heterozygous for OTCD and developed acute hyperammonemia during pregnancy.Her blood showed a normal-leveled arginine (8.44 μ mol/L,reference 1.50-25.00 μ mol/L),a normal-leveled citrulline(8.41 μ mol/L,reference 7.00-35.00 μ mol/L),an elevated glutamate(279.15 μ mol/L,reference 45.00-200.00 μ mol/L).Her urine uracil (51.55 μ mol/mol Crea,reference 0.00-7.00 μ mol/mol Crea) and orotic acid (38.75 μ mol/mol Crea,reference 0.00-1.50 μ mol/mol) were elevated.Successful management of her prenatal and postpartum blood ammonia level was achieved after administration of pharmacologic nitrogen scavengers and protein limitation.DNA studies revealed a c.583G ＞ A (G195R) heterozygous mutation in the newborn's mother and grandmother.Conclusions General management on pregnant OTCD women is effective.Male newborn patients often have a poor prognosis.