Treatment and management for children with urea cycle disorder in chronic stage / 浙江大学学报·医学版

Urea cycle disorder (UCD) is a group of inherited metabolic diseases with high disability or fatality rate, which need long-term drug treatment and diet management. Except those with Citrin deficiency or liver transplantation, all pediatric patients require lifelong low protein diet with safe levels of protein intake and adequate energy and lipids supply for their corresponding age; supplementing essential amino acids and protein-free milk are also needed if necessary. The drugs for long-term use include nitrogen scavengers (sodium benzoate, sodium phenylbutyrate, glycerol phenylbutyrate), urea cycle activation/substrate supplementation agents (N-carbamylglutamate, arginine, citrulline), etc. Liver transplantation is recommended for pediatric patients not responding to standard diet and drug treatment, and those with severe progressive liver disease and/or recurrent metabolic decompensations. Gene therapy, stem cell therapy, enzyme therapy and other novel technologies may offer options for treatment in UCD patients. The regular biochemical assessments like blood ammonia, liver function and plasma amino acid profile are needed, and physical growth, intellectual development, nutritional intake should be also evaluated for adjusting treatment in time.

Clinical and Genetic Characterization and Biochemical Correlation at Presentation in 48 Patients Diagnosed with Urea Cycle Disorders at the Hospital Juan P Garrahan, Argentina

Abstract The clinical and biochemical findings in a cohort of 51 patients with urea cycle disorders followed at the Hospital Garrahan, Buenos Aires, Argentina were analyzed at the time of diagnosis (3 female patients were excluded). Of this cohort, 13/48 patients had early-onset (EO), 23/48 had late-onset (LO), and 12/48 had a different presentation because they had a family risk background (FRB) and had been diagnosed since they were born. The most frequent deficiency disorder was OTCD (65%). The initial ammonium value was evaluated, being higher in the EO group, with a statistically significant difference when compared with LO and FRB. 15/48 patients fell into a coma at the time of diagnosis, mean ammonia was 829.54 μmol / L, and 33/48 did not fell into a coma, the mean ammonium was of 159.3 μmol / L (p = 0.001). 15 patients died: 62% EO, 22% LO (p=0.0216), 17% FRB. A molecular study was performed on 35 patients. Patients with EO presentation suffer the most severe forms and still have high morbimortality. On the other hand, LO forms are forms of less severity that are finally diagnosed as a result of one or more acute episodes.

Clinical diagnosis and treatment of three cases with hyperornithinemia-hyperammonemia-homocitrullinuria syndrome / 中华儿科杂志

Objective@#To study the clinical characteristics, methods of diagnosis and treatment of hyperornithinemia-hyperammonemia- homocitrullinuria (HHH) syndrome.@*Method@#From July 2011 to August 2016, 3 Chinese patients with HHH syndrome were enrolled in this study. The clinical course, biochemical features, brain MRI findings, and gene mutations were analyzed.@*Result@#The three patients′ age at onset of symptoms was 3 months to 7 years, and the age of diagonosis was 3 years and 10 months to 9 years and 10 months. All of them presented with intolerance to protein-rich foods from the infant period, development retardation and abnormal posture. Case 1 and 2 had moderate mental retardation. Serum ammonia 25-276 μmol/L (reference range<60 μmol/L), alanine aminotransferase (ALT) 20-139 IU/L (reference range 9-50 IU/L), ornithine 29.12-99.44 μmol/L(reference range 15-100 μmol/L), urinary orotic acid 1.49-29.75 mmol/mol Cr (reference range 0-7 mmol/mol Cr), uracil 6.09-103.97 mmol/mol Cr (reference range 0-1.5 mmol/mol Cr). The cranial MRI revealed lesions in the basal ganglia, abnormal white matter signal, progressive demyelination and cerebral atrophy. On their SLC25A15 gene, a novel homozygous missense mutation c. 416A>G (p.E139G) was identified in case 1, a known pathogenic homozygous nonsense mutation c. 535C>T was found in case 2 and 3. Liver transplantation had been performed when case 1 was 6 years old. Significant improvements were observed in dietary habit, mental and motor functions, and biochemical parameters. After the dietary intervention with the supplements of arginine, L-carnitine, case 2 was improved, spastic paraplegia of case 3 had no mitigation. Liver transplant was recommended.@*Conclusion@#HHH syndrome has an aversion to protein-rich food, and the patients have recurrent vomiting and progressive neurological dysfunction. Clinical diagnosis of HHH syndrome is difficult and patients may present with incomplete biochemical phenotype. The genetic analysis is key for the diagnosis. Depending on their condition, individuals with HHH syndrome can be treated with a low-protein diet, drugs and liver transplantation.

Lysinuric Protein Intolerance Presenting with Recurrent Hyperammonemic Encephalopathy.

Background: Lysinuric protein intolerance is an inherited disorder of transport of cationic amino acids, causing amino aciduria. Case characteristics: A 3-year-old boy with 12 month history of episodic change in behavior (decreased sleep, poor interaction), stunted growth and hyperammonemia. Outcome: Genetic analysis revealed a homozygous mutation, c.158C>T (p.Ser53Leu) in exon 1 of SLC7A7 gene.With appropriate management of hyperammonemia episodes, his neurodevelopmental outcome is normal. Message: Lysinusic protein intolerance is a potentially treatable disorder and should not to be missed.

Diagnosis and treatment of urea cycle disorder and hyperammonemia / 中国小儿急救医学

Urea cycle disorder is a common inherited metabolic disorder,and it is the most common genetic cause of hyperammoniema in children.The illness is believed to be caused by gene mutation of six main enzymes in urea cycle,leading to ammonia,which is produced by amino acid catabolism,can't conver to urea through the urea cycle and be discharged through the urine.The manifestations of hyperammonemia turn out to be disorders of brain function (refusing to milk,vomiting,drowsiness,coma,convulsions,ataxia,aggressive behaviors).The incidence of this disease is 1/30 000.At the same time,the severity of the clinical symptoms is connected with the extent of the enzymes defects.More serious the enzymes defected,the earlier and worse the disease onsets.Some children with mild enzyme defects may intermittently attack or have a delay onset.Serious nervous system injuries can be found in hyperammonernia,therefore,early diagnosis and treatment must be ensured in order to decrease risk of mental injuries and damages or acute deaths.

Clinical and pedigree analysis of late onset congenital ornithine transcarbamylase deficiency in a child / 中华内分泌代谢杂志

Objective To raise the awareness of congenital ornithine transcarbamylase deficiency (OTCD) by analyzing the clinical features and the family pedigree in a child with OTCD.Methods Clinical characteristics were analyzed in a child with OTCD.The genetic analysis was performed in ten exons and nine intron-exon boundaries in the ornithine transcarbamylase (OTC) gene of the case and his family by direct sequencing of PCR-DNA from peripheral blood.Family history including his grandparents and uncle was registered.Results The onset age of the case was 6 months old,the clinical picture was characterized by recurrent episodes of vomiting,low spirits,hyperammonemia,and abnormal liver function.His brother died of the similar performance at 6 months old.His sister was healthy.IVS1-2A＞G intron mutation of OTC gene was found in the case,while his mother and sister were the carriers and his father revealed no mutation.His maternal grandparents and his uncle's family were healthy.Conclusion OTCD is a kind of congenital genetic disease,and is one of the main causes of hyperammonemia.Misdiagnosis is very common because clinical symptoms of this disease are variable.IVS1-2A＞G mutation in OTC gene is the pathogeny of this case.The family genealogy indicates that this case is a kind of X-linked recessive hereditary disease.

Venovenous Hemodiafiltration and Hypothermia for Treatment of Cerebral Edema Associated With Hyperammonemia.

We report a 50-hour-old newborn with inborn urea cycle disorder and hyperammonia of 2320 μmol/L. The pharmacological treatment of the first metabolic crisis was combined with venovenous hemodiafiltration and therapeutic hypothermia to rescue the patient from a life-threatening cerebral edema.

Hyperammonemia in a Patient with Late-Onset Ornithine Carbamoyltransferase Deficiency

Ornithine carbamoyltransferase (OTC) deficiency is a urea cycle disorder that causes the accumulation of ammonia, which can lead to encephalopathy. Adults presenting with hyperammonemia who are subsequently diagnosed with urea cycle disorders are rare. Herein, we report a case of a late-onset OTC deficient patient who was successfully treated with arginine, benzoate and hemodialysis. A 59-yr-old man was admitted to our hospital with progressive lethargy and confusion. Although hyperammonemia was suspected as the cause of the patient's mental changes, there was no evidence of chronic liver disease. A plasma amino acid and urine organic acid analysis revealed OTC deficiency. Despite the administration of a lactulose enema, the patient's serum ammonia level increased and he remained confused, leading us to initiate acute hemodialysis. After treatment with arginine, sodium benzoate and hemodialysis, the patient's serum ammonia level stabilized and his mental status returned to normal.

A Case with Transient Hyperammonemia of Newborn

Hyperammonemia in the newborn often leads to severe fatal illness associated with hyperammonemic encephalopathy. Transient hyperammonemia in newborns (THAN) is characterized by self-limiting, transient hyperammonemia during the neonatal period. THAN may have favorable long-term outcomes if it is diagnosed early and appropriately managed. However, severe hyperammonemia can develop even in newborns with THAN, which may require emergent management. Here we report a case of THAN with severe hyperammonemia during the neonatal period that was successfully treated with continuous renal replacement therapy and nitrogen-scavenging medications. Our patient went on to develop normally and has not re-experienced a hyperammonemic episode until 9 months of age without the administration of a protein restricted diet or medications.

Successful treatment of a child with citrullinemia

The amino acids formed by degradation of proteins ingested produce ammonia. The ammonia which is broken down and excreted as urea through a process known as the Klebs-Hensleit cycle or the urea cycle. 1) The urea cycle consists of five enzymes necessary for the synthesis of carbamyl phosphate, citrulline, argininosuccinate, arginine, and urea: carbamyl phosphate synthetase (CPS), ornithine transcarbamylase (OTC), argininosuccinate synthetase (AS), argininosuccinate lyase (AL), and arginase (ARG). 2) Congenital deficiencies of the enzymes involved in the urea cycle are diseases that are almost fatal without treatment, showing symptoms like vomiting, lethargy, dyspnea, and coma due to hyperammonemia coming from the accumulation of ammonia and metabolic precursors resulting from the deficiency of one of these enzymes. 3) Among these, the disease manifested by the congenital deficiency of argininosuccinate synthetase (AS) which is associated with the formation of argininosuccinate in citrulline is called argininosuccinate synthetase deficiency or citrullinemia. There have been two reports on this so far in Korea; one in July 1987 by Kim et al. 4) and the other by Park et al. 5) in 1995. We are to report a case of successful treatment of a child with citrullinemia who was transferred to our hospital due to dyspnea, lethargy, feeding difficulties, convulsions and cyanosis together with some document studies related to this case.