Manejo inicial de la hiperamonemia aguda en pediatría / Initial management of acute hyperammonemia in pediatrics

La hiperamonemia constituye una emergencia médica. No existen publicaciones que hagan referencia a la disponibilidad de recursos, insumos y conocimientos necesarios para el manejo inicial de esta por parte del pediatra en nuestro país, pero, según la experiencia de los autores, los recursos necesarios no se encuentran disponibles los 365 días del año en una gran porción de nuestro territorio. Sobre la base de este estado de situación, de una revisión bibliográfica internacional sobre el tema y de la experiencia de los autores, se elaboraron una serie de recomendaciones para el manejo pediátrico inicial de esta emergencia, que tienen como objetivo poder reducir las deficiencias, permitir una sospecha clínica adecuada que lleve a un diagnóstico y tratamiento de emergencia oportunos, con utilización racional de recursos farmacológicos (algunos de ellos de alto costo), para reducir la morbimortalidad que asocia la patología.

Hyperammonemia is a medical emergency. There are no publications regarding the availability of resources, supplies, and knowledge necessary for the initial management of hyperammonemia by pediatricians in Argentina; however, according to the authors' experience, the necessary resources are not available all year round in a large portion of our territory. Based on such state of affairs, an international bibliographic review on this topic and the authors' experience, we developed a series of recommendations for the initial pediatric management of this emergency, with the objective of reducing deficiencies, allowing adequate clinical suspicion leading to a timely diagnosis and emergency management and a rational use of pharmacological resources (some of which are costly) to reduce the morbidity and mortality associated with hyperammonemia.

Analysis of blood carnitine profile and SLC22A5 gene variants in 17 neonates with Primary carnitine deficiency / 中华医学遗传学杂志

OBJECTIVE@#To analyze the blood free carnitine (C0) level and SLC22A5 gene variants in 17 neonates with Primary carnitine deficiency (PCD) and to determine its incidence in local area and explore the correlation between C0 level and genotype.@*METHODS@#148 043 newborns born in 9 counties (cities and districts) of Ningde city from September 2016 to June 2021 were selected as study subjects. Blood free carnitine and acyl carnitine of 148 043 neonates were analyzed. Variants of the SLC22A5 gene were screened in those with blood C0 < 10 µmol/L, or C0 between 10 ∼ 15 µmol/L. Correlation between the free carnitine level and genetic variants was analyzed.@*RESULTS@#In total 17 neonates were diagnosed with PCD, which yielded a prevalence of 1/8 707 in the region. Twelve variants of the SLC22A5 gene were identified, with the common ones including c.760C>T, c.1400C>G and c.51C>G. Compared with those carrying other variants of the gene, children carrying the c.760C>T variant had significantly lower C0 values (P < 0.01).@*CONCLUSION@#The prevalence of PCD is relatively high in Ningde area, and intervention measures should be taken to prevent and control the disease. The c. 760C>T variant is associated with lower level of C0, which can provide a clue for the diagnosis.

Expert consensus on the diagnosis and treatment of neonatal hyperammonemia / 中国当代儿科杂志

Neonatal hyperammonemia is a disorder of ammonia metabolism that occurs in the neonatal period. It is a clinical syndrome characterized by abnormal accumulation of ammonia in the blood and dysfunction of the central nervous system. Due to its low incidence and lack of specificity in clinical manifestations, it is easy to cause misdiagnosis and missed diagnosis. In order to further standardize the diagnosis and treatment of neonatal hyperammonemia, the Youth Commission, Subspecialty Group of Neonatology, Society of Pediatrics, Chinese Medical Association formulated the expert consensus based on clinical evidence in China and overseas and combined with clinical practice experience,and put forward 18 recommendations for the diagnosis and treatment of neonatal hyperaminemia.

Neonate-onset ornithine transcarbamylase deficiency / 中国当代儿科杂志

The male neonate in this case study was admitted to the hospital at 15 hours of age due to respiratory distress for 15 hours and poor response for 3 hours after resuscitation from asphyxia. The neonate was highly unresponsive, with central respiratory failure and seizures. Serum ammonia was elevated (>1 000 μmol/L). Blood tandem mass spectrometry revealed a significant decrease in citrulline. Rapid familial whole genome sequencing revealed OTC gene mutations inherited from the mother. Continuous hemodialysis filtration and other treatments were given. Neurological assessment was performed by cranial magnetic resonance imaging and electroencephalogram. The neonate was diagnosed with ornithine transcarbamylase deficiency combined with brain injury. He died at 6 days of age after withdrawing care. This article focuses on the differential diagnosis of neonatal hyperammonemia and introduces the multidisciplinary management of inborn error of metabolism.

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.

Application of continuous renal replacement therapy in the treatment of neonates with inherited metabolic diseases / 中国当代儿科杂志

OBJECTIVE@#To study the efficacy and safety of continuous renal replacement therapy (CRRT) in the treatment of neonates with inherited metabolic diseases and hyperammonemia.@*METHODS@#A retrospective analysis was performed on the medical records of neonates with inherited metabolic diseases and hyperammonemia who were hospitalized and underwent CRRT in the Department of Neonatology, Hunan Children's Hospital, from September 2016 to March 2020, including general conditions, clinical indices, laboratory markers, and adverse reactions.@*RESULTS@#A total of 11 neonates were enrolled, with 7 boys (64%) and 4 girls (36%). The neonates had a mean gestational age of (38.9±0.8) weeks, a mean body weight of (3 091±266) g on admission, and an age of (5.7±2.0) days at the time of CRRT. The main clinical manifestations were vomiting (100%), convulsions (100%), and coma (55%), and the main primary disease was urea cycle disorder (55%). The mean duration of CRRT was (44±14) hours, the medium duration of coma before CRRT was 2 hours, and the total duration of coma was 10 hours. The patients had a mean hospital stay of (18±10) days and a survival rate of 73%, and 2 survivors had epilepsy. After treatment, all patients had significant reductions in blood ammonia, lactic acid, and K@*CONCLUSIONS@#CRRT is safe and effective in the treatment of neonates with inherited metabolic diseases and hyperammonemia.

Analysis of metabolic profile and genetic variants for newborns with primary carnitine deficiency from Guangxi / 中华医学遗传学杂志

OBJECTIVE@#To analyze the metabolic profile and genetic variants for newborns with primary carnitine deficiency (PCD) from Guangxi, China.@*METHODS@#From January 2014 to December 2019, 400 575 newborns from the jurisdiction of Guangxi Zhuang Autonomous Region Newborn Screening Center were subjected to tandem mass spectrometry (MS/MS) analysis. Newborns with positive results for PCD and their mothers were recalled for retesting. Those who were still positive were subjected to sequencing of the SLC22A5 gene.@*RESULTS@#Twenty-two newborns and 9 mothers were diagnosed with PCD, which gave a prevalence rate of 1/18 208. Sequencing of 18 newborns and 4 mothers have identified 14 types of SLC22A5 gene variants, with the common ones including c.51C>G (10/44, 22.7%), c.1195C>T (9/44, 20.5%) and c.1400C>G (7/44, 15.9%), The c.517delC(p.L173Cfs*3) and c.1031C>T(p.T344I) were unreported previously and predicted to be pathogenic (PVS1+PM2_supporting+PM3+PP4) and likely pathogenic (PM1+PM2_supporting+PM3+PP3+PP4) based on the American College of Medical Genetics and Genomics standards and guidelines.@*CONCLUSION@#c.51C>G, c.1195C>T and c.1400C>G are the most common variants underlying PCD in Guangxi.

Un trastorno poco frecuente del ciclo de la urea en un recién nacido: deficiencia de N-acetilglutamato sintasa / A rare urea cycle disorder in a neonate: N-acetylglutamate synthetase deficiency

Los trastornos del ciclo de la urea (TCU) son enfermedades hereditarias con un posible desenlace desfavorable por hiperamoniemia grave. Se informa de una bebé con deficiencia de N-acetilglutamato sintasa (NAGS), quien tenía succión débil e hipotonicidad. Al examinarla, se observó hepatomegalia. El hemograma, los análisis y la gasometría eran normales, y las proteínas de la fase aguda, negativas. En los análisis, no se observaron cetonas en sangre, pero sí concentraciones elevadas de amoníaco. Las pruebas metabólicas no fueron concluyentes. Se inició el tratamiento de emergencia inmediatamente y recibió el alta el día 15 después del ingreso. Se confirmó deficiencia de NAGS mediante análisis de ADN. La paciente no tiene restricciones alimentarias ni toma medicamentos, excepto N-carbamil glutamato (NCG). La deficiencia de NAGS es el único TCU que puede tratarse específica y eficazmente con NCG. La detección temprana permite iniciar un tratamiento temprano y evitar los efectos devastadores de la hiperamoniemia

Urea cycle disorders (UCD), are genetically inherited diseases that may have a poor outcome due to to profound hyperammonemia. We report the case of a baby girl diagnosed as N-acetylglutamate synthase (NAGS) deficiency.The patient was evaluated due to diminished sucking and hypotonicity. Physical examination showed hepatomegaly. Complete blood count, biochemical values and blood gas analyses were normal, acute phase reactants were negative. Further laboratory analyses showed no ketones in blood and highly elevated ammonia. Metabolic tests were inconclusive. Emergency treatment was initiated immediately and she was discharged on the 15th day of admission. NAGS deficiency was confirmed by DNA-analysis. She is now without any dietary restriction or other medication, except N-carbamylglutamate (NCG).NAGS deficiency is the only UCD which can be specifically and effectively treated by NCG. Early recognition of disease will lead to early treatment that may prohibit devastating effects of hyperammonemia

Acidemia propiónica: diagnóstico clínico vs. cribado neonatal / Propionic acidemia: clinical diagnosis vs newborn screening

La acidemia propiónica es una rara enfermedad metabólica (prevalencia: 1/100 000), cuya detección puede hacerse de forma precoz mediante el cribado neonatal en las primeras 72 horas de vida. Puede tener una presentación neonatal grave, tardía intermitente o crónica progresiva. El tratamiento de las crisis consiste en la inversión del catabolismo que detiene la ingesta proteica con aporte intravenoso de calorías no proteicas. La mortalidad depende, fundamentalmente, de los episodios de descompensación aguda, mientras que la evolución asocia una alta tasa de secuelas neurológicas y déficits cognitivos.Se presenta el caso de una recién nacida de 11 días de vida con clínica de estancamiento ponderal, letargia, acidosis metabólica e hiperamonemia, que, debido a una falla en el proceso de cribado, no se benefició del diagnóstico precoz.A pesar de la ya existente detección por cribado, es vital mantener un alto índice de sospecha en casos sugestivos de metabolopatías.

Propionic acidemia is a rare metabolic disease (prevalence 1/100,000) that can be early detected with the newborn metabolic screening within the first 72 hours of life. It can have a severe neonatal presentation, a late intermittent onset or a chronic and progressive course. The treatment in the crisis consists in inverting the catabolism by pausing the protein intake and giving intravenous non-protein calories. Mortality depends mainly on acute episodes of decompensation, while evolution and prognosis associate a high rate of neurological sequelae and cognitive deficiencies.We present the case of an 11-day-old female newborn with failure to thrive, lethargy, metabolic acidosis and hyperammonemia that, because of a failed newborn screening process, could not be early diagnosed.In spite of the existence of early detection with the newborn metabolic screening, it is very important to keep a high suspicion in cases that suggest metabolic disorders.

Biochemical and genetic characteristics of 40 neonates with carnitine deficiency / 中南大学学报(医学版)

OBJECTIVES@#Primary carnitine deficiency (PCD) is a rare fatty acid metabolism disorder that can cause neonatal death. This study aims to analyze carnitine levels and detect SLC22A5 gene in newborns with carnitine deficiency, to provide a basis for early diagnosis of PCD, and to explore the relationship between carnitine in blood and SLC22A5 genotype.@*METHODS@#A total of 40 neonates with low free carnitine (C0G (p.Y251C), c.495 C>A (p.R165E), and c.1298T>C (p.M433T). We found 14 PCD patients including 2 homozygous mutations and 12 heterozygous mutations, 14 with 1 mutation, and 12 with no mutation among 40 children. The C0 concentration of children with SLC22A5 gene homozygous or complex heterozygous mutations was (4.95±1.62) μmol/L in the initial screening, and (3.90±1.33) μmol/L in the second screening. The C0 concentration of children with no mutation was (7.04±2.05) μmol/L in the initial screening, and (8.02±2.87) μmol/L in the second screening. There were significant differences between children with homozygous or compound heterozygous mutations and with no mutation in C0 concentration of the initial and the second screening (both @*CONCLUSIONS@#There are 5 new mutations which enriched the mutation spectrum of SLC22A5 gene. C0<5 μmol/L is highly correlated with SLC22A5 gene homozygous or compound heterozygous mutations. Children with truncated mutation may have lower C0 concentration than that with untruncated mutation in the initial screening.

Consensus on diagnosis and treatment of ornithine trans-carbamylase deficiency / 浙江大学学报·医学版

Ornithine transcarbamylase deficiency(OTCD)is a most common ornithine cycle (urea cycle) disorder. It is a X-link inherited disorder caused by

Hiperamonemia secundaria a infección urinaria en un paciente con malformación del tracto urinario en pediatría: a propósito de un caso / Hyperammonemia secondary to urinary tract infection in patients with pediatric urinary tract malformation: a case report

Ammonium is an important source of nitrogen for amino acid synthesis and is necessary for normal acid base balance. When ammonium concentrations are high it becomes a toxic compound. Hyperammonemia is a metabolic emergency. When underdiagnosed and not treated appropriately, it produces severe neurological sequelae and/or death. The clinical presentation of hyperammonemic encephalopathy varies, and includes from personality disorders, psychiatric disorders, confusion, irritability, lethargy, seizures to coma. Hyperammonemia occurs with an increase in ammonium production, as in intestinal hemorrhage, or with a decrease in the elimination of ammonium, such as in congenital metabolic errors, hepatic insufficiency or drug intoxication. As we can see, it may have multiple origins, but congenital errors of metabolism are always suspected as one of the causes. However, there are less frequent causes, such as urinary tract infection, especially in predisposing conditions. We describe the case of a 2-year-old boy with a history of horseshoe kidney and right ureterohydronephrosis, surgical correction of imperforate anus and rectal bladder fistula. This patient presented hyperammonemia with encephalopathy (Glasgow 7/15) while undergoing a urinary infection with Corynebacterium riegelii. Hyperammonemia is the result of the production in the dilated urinary tract of large amounts of ammonium due to bacterial urease and its subsequent reabsorption in the systemic circulation. The patient improved clinically (Glasgow 15/15) after parenteral antibiotic therapy and urinary tract clearance

El amonio es una fuente importante de nitrógeno para la síntesis de aminoácidos y necesario para el balance ácido base; si se encuentra elevado, se convierte en un compuesto tóxico. La hiperamoniemia es una urgencia metabólica; cuando no es diagnosticada y tratada de manera oportuna, produce graves secuelas de tipo neurológico o la muerte. La presentación clínica de la encefalopatía hiperamoniémica es variable, pudiéndose observar trastornos en la personalidad, trastornos psiquiátricos, confusión e irritabilidad, letargia, convulsión y coma. La hiperamoniemia se presenta por aumento en la producción de amonio, como en la hemorragia intestinal, o por disminución de la eliminación del mismo, como ocurre en los errores congénitos del metabolismo, en la insuficiencia hepática o en la intoxicación por fármacos. Puede tener múltiples orígenes, pero los errores congénitos del metabolismo son una de las causas que siempre se sospechan. Sin embargo, existen causas menos frecuentes, como la infección del tracto urinario (sobre todo en condiciones que predispongan a las mismas). Describimos aquí el caso de un niño de 2 años, con antecedentes de riñón en herradura y ureterohidronefrosis derecha, corrección quirúrgica de ano imperforado y fistula recto vesical. Este paciente presentó hiperamoniemia con encefalopatía (Glasgow 7/15) mientras cursaba una infección urinaria por Corynebacterium riegelii. La hiperamoniemia es el resultado de la producción en el tracto urinario dilatado de grandes cantidades de amonio, debido a la ureasa bacteriana y su posterior reabsorción en la circulación sistémica. El paciente mejoró clínicamente (Glasgow 15/15) después de la terapia antibiótica parenteral y desobstrucción de tracto urinario

Genetic diagnosis of a Chinese pedigree affected with neonatal argininosuccinic aciduria / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of a neonate with argininosuccinic aciduria (ASA).@*METHODS@#A neonate with lethargy and food refusal was admitted. The patient had myoclonus, myasthenia, uroschesis, irregular breathing and paroxysmal ventricular tachycardia, and died at 75 hours after birth. Laboratory test showed marked increase in blood ammonia (1249.8 μmol/L). Peripheral blood samples of the patient, her parents and sister were collected and subjected to trio whole-exome sequencing.@*RESULTS@#Whole-exome sequencing revealed that the patient has carried compound heterozygous mutations of the argininosuccinate lyase (ASL) gene, namely c.425(exon5)_c.426(exon5) insAGCTCCCAGCT (p.Thr142Thrfs*37) and c.626(exon8)delT (p.Leu209Argfs*42). The patient was diagnosed as ASA caused by ASL gene mutations. Her parents and her elder sister were heterozygous carriers of the above mutations and had a normal phenotype.@*CONCLUSION@#ASA is a severe congenital genetic metabolic disease and can manifest as onset of hyperammonemia in neonates. The clinical diagnosis is difficult and ASL gene testing may be helpful.

Nutritional Therapy Related Complications in Hospitalized Adult Patients: A Korean Multicenter Trial

PURPOSE: Nutritional therapy (NT), such as enteral nutrition (EN) or parenteral nutrition (PN), is essential for the malnourished patients. Although the complications related to NT has been well described, multicenter data on symptoms in the patients with receiving NT during hospitalization are still lacking. METHODS: Nutrition support team (NST) consultations, on which NT-related complications were described, were collected retrospectively for one year. The inclusion criteria were patients who were (1) older than 18 years, (2) hospitalized, and (3) receiving EN or PN at the time of NST consultation. The patients' demographics (age, sex, body mass index [BMI]), type of NT and type of complication were collected. To compare the severity of each complication, the intensive care unit (ICU) admission, hospital stay, and type of discharge were also collected. RESULTS: A total of 14,600 NT-related complications were collected from 13,418 cases from 27 hospitals in Korea. The mean age and BMI were 65.4 years and 21.8 kg/m2. The complications according to the type of NT, calorie deficiency (32.4%, n=1,229) and diarrhea (21.6%, n=820) were most common in EN. Similarly, calorie deficiency (56.8%, n=4,030) and GI problem except for diarrhea (8.6%, n=611) were most common in PN. Regarding the clinical outcomes, 18.7% (n=2,158) finally expired, 58.1% (n=7,027) were admitted to ICU, and the mean hospital days after NT-related complication were 31.3 days. Volume overload (odds ratio [OR]=3.48) and renal abnormality (OR=2.50) were closely associated with hospital death; hyperammonemia (OR=3.09) and renal abnormality (OR=2.77) were associated with ICU admission; “micronutrient and vitamin deficiency” (geometric mean [GM]=2.23) and volume overload (GM=1.61) were associated with a longer hospital stay. CONCLUSION: NT may induce or be associated with several complications, and some of them may seriously affect the patient's outcome. NST personnel in each hospital should be aware of each problem during nutritional support.

Sarcopenia: Ammonia metabolism and hepatic encephalopathy

Sarcopenia (loss of muscle mass and/or strength) frequently complicates liver cirrhosis and adversely affects the quality of life; cirrhosis related liver decompensation and significantly decreases wait-list and post-liver transplantation survival. The main therapeutic strategies to improve or reverse sarcopenia include dietary interventions (supplemental calorie and protein intake), increased physical activity (supervised resistance and endurance exercises), hormonal therapy (testosterone), and ammonia lowering agents (L-ornithine L-aspartate, branch chain amino acids) as well as mechanistic approaches that target underlying molecular and metabolic abnormalities. Besides other factors, hyperammonemia has recently gained attention and increase sarcopenia by various mechanisms including increased expression of myostatin, increased phosphorylation of eukaryotic initiation factor 2a, cataplerosis of α ketoglutarate, mitochondrial dysfunction, increased reactive oxygen species that decrease protein synthesis and increased autophagy-mediated proteolysis. Sarcopenia contributes to frailty and increases the risk of minimal and overt hepatic encephalopathy.

Efficacy of L-carnitine on ribavirin-induced hemolytic anemia in patients with hepatitis C virus infection

BACKGROUND/AIMS: L-carnitine not only alleviates hyperammonemia and reduces muscle cramps in patients with liver cirrhosis, but also improves anemia in patients with chronic hepatitis and renal dysfunction. This study prospectively evaluated the preventative efficacy of L-carnitine supplementation against hemolytic anemia during antiviral treatment using ribavirin in patients with hepatitis C virus (HCV)-related chronic liver disease. METHODS: A total of 41 patients with chronic hepatitis were consecutively enrolled in this study. Group A (n=22) received sofosbuvir plus ribavirin for 3 months, whereas group B (n=19) was treated with sofosbuvir, ribavirin, and L-carnitine. Hemoglobin concentration changes, the effects of antiviral treatment, and the health status of patients were analyzed using short form-8 questionnaires. RESULTS: A significantly smaller decrease in hemoglobin concentration was observed in group B compared to group A at every time point. Moreover, the prescribed dose intensity of ribavirin in group B was higher than that of group A, resulting in a higher ratio of sustained virological response (SVR) 24 in group B compared with group A. The physical function of patients in group B was also significantly improved compared to group A at the end of antiviral treatment. CONCLUSIONS: L-carnitine supplementation alleviates ribavirin-induced hemolytic anemia in patients with HCV and helps relieve the physical burden of treatment with ribavirin-containing regimens. These advantages significantly increase the likelihood of achieving SVR.

Renal replacement therapy in neonates with an inborn error of metabolism / 소아과

Hyperammonemia can be caused by several genetic inborn errors of metabolism including urea cycle defects, organic acidemias, fatty acid oxidation defects, and certain disorders of amino acid metabolism. High levels of ammonia are extremely neurotoxic, leading to astrocyte swelling, brain edema, coma, severe disability, and even death. Thus, emergency treatment for hyperammonemia must be initiated before a precise diagnosis is established. In neonates with hyperammonemia caused by an inborn error of metabolism, a few studies have suggested that peritoneal dialysis, intermittent hemodialysis, and continuous renal replacement therapy (RRT) are effective modalities for decreasing the plasma level of ammonia. In this review, we discuss the current literature related to the use of RRT for treating neonates with hyperammonemia caused by an inborn error of metabolism, including optimal prescriptions, prognosis, and outcomes. We also review the literature on new technologies and instrumentation for RRT in neonates

Clinical and genetic analysis of two children suspected for argininosuccinic aciduria / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical and genetic features of two children suspected for arginylsuccinuria aciduria.@*METHODS@#The patients were subjected to high-throughput sequencing using a gene panel.@*RESULTS@#Both patients had high citrulline (87.37-156.10 μmol/L) measured by mass spectrometry/mass spectrometry (MS/MS) upon neonatal screening but had no symptoms. Two compound heterozygous variants of the ASL gene were detected in patient 1 (exon 6: c.467C>T inherited from her father and exon 7: c.556C>T inherited from her mother), among which c.556C>T is novel. Patient 2 had mental retardation and two full siblings who had died of hyperammonemia. Two compound heterozygosity variants of the ASL gene were detected (exon 3: c.281G>T inherited from his father and intron: c.208-15T>A inherited from his mother). Both were novel mutations.@*CONCLUSION@#Variants of the ASL gene probably underlie the argininosuccinic aciduria in the two patients. Above findings have enriched the spectrum of ASL mutations.