Glyceryl phenylbutyrate in the treatment of argininosuccinate synthetase deficiency: a case report / 中华实用儿科临床杂志

Clinical data of a child with high blood ammonia and suspected argininosuccinate synthetase deficiency (ASSD) in Hunan Children′s Hospital were retrospectively analyzed, including data of mass spectra for blood amino acids and acyl carnitine, urine organic acid analysis and whole exome sequencing.After the exact diagnosis of ASSD and being approved by the Administrative Regulation for Import Medical Devices Urgently Needed in Boao Lecheng International Medical Tourism Pilot Zone of Hainan Free Trade Port, the patient was medicated with Glyceryl phenylbutyrate (GPB) and followed up.The patient was a boy aged 7 years and 8 months, who presented at the Neurology Department of Hunan Children′s Hospital for sleepiness, abnormal mental behavior and personality change for 1 week on December 2, 2021.Before GPB treatment, the highest blood ammonia, alanine aminotransferase and aspartate transaminase were 325.2 μmol/L, 465.7 IU/L and 277.3 IU/L, respectively.Genetic metabolism assay of blood and urine showed a significantly increased citrulline at 697.42 μmol/L; urine organic acid analysis showed increased urinary orotic acid at 144.2 μmol/L, and increased uracil at 65.1 μmol/L.A pure heterozygous variant of the ASS1 gene (c.1087C>T, p.R363W) was detected.After GPB treatment, the blood ammonia levels were 21.3 μmol/L, 54.6 μmol/L and 62.4 μmol/L on the 41 st, 90 th and 146 th days, respectively.Until July 20, 2022 follow-up visit, the patient recovered well without adverse events.This was the first ASSD child in China who was treated with GPB.This case report provided therapeutic experience of ASSD in our country.ASSD has a high mortality rate and unexplained abnormal mental behavior.It is necessary to timely measure blood ammonia, and a series of urea cycle disorders should be well concerned.The diagnosis and management of ASSD rely on the data of metabolism examination and genetic testing.

Anesthetic Management in a Adult Male with Citrullinemia: A Case Report

Our case report is regarding a patient who is a k/c/o citrullinemia type 1 which is a defect in urea cycle posted for facture patella reduction surgery (tension band wiring). He was intellectual disabled because of persistent hyperammonaemia before diagnosis that was controlled with benzoate and L- arginine. Patient preoperative fasting was kept to the minimum and taken as 1st case in the operation theatre. Drugs taken orally on routine basis were continued along with serum ammonia monitoring. Clonidine with midazolam along with propofol infusion to decrease protein hypercatabolism due to stress and to get co-operation of the patient for femoral sciatic block. Postoperative ammonia levels were normal. Sedation is considered useful for preventing hyper ammonemia. Preoperative endocrinology consultation, perioperative serum ammonia level monitoring and coordination between various health departments (nephrologist and endocrinologist) for appropriate care in case of hyper ammonemia and hyperglycaemia perioperatively.

Clinical value of split domino donor auxiliary liver transplantation / 中华消化外科杂志

Objective:To investigate the clinical value of split domino donor auxiliary liver transplantation.Methods:The retrospective and descriptive study was conducted. The clinco-pathological data of 3 liver transplantation recipients who were admitted to Nanjing Drum Tower Hospital affiliated to Nanjing University Medical School and 1 liver transplantation recipient who was admitted to external hospital in September 2018 were collected. The first case was male, aged 22 years, who was diagnosed as type II citrullinemia (CTLN2). The second case undergoing liver transplantation in external hospital was male, aged 59 years, who was diagnosed as decompensated alcoholic cirrhosis. The third case was female, aged 52 years, who was diagnosed as hepatocellular carcinoma of right lobe of liver. The fourth case was female, aged 51 years, who was diagnosed as hepatocellular carcinoma of right lobe of liver. The donor liver from a brain and cardiac death donor was split in vitro into the left liver and the right liver, in which the right liver without middle hepatic vein, and the modified piggyback liver transplantation using the left liver and the classical orthotropic liver transplantation using the right liver was conducted on the first and the second case, respectively. The original liver of the first case was split in vivo into the left liver and the right liver, and the piggyback auxiliary liver transplantation using the left liver and the piggyback auxiliary liver transplantation using the right liver was conducted on the third and the fourth case who underwent extended right hemihepatectomy, respectively. Observation indicators: (1) intraoperative situations; (2) follow-up. Follow-up was conducted using outpatient examination and telephone interview to detect liver function, liver imaging, complication and survival of recipients up to October 2021.Results:(1) Intraoperative situations. Liver transplantation was conducted successfully on the first, third and fourth case, with the operation time, the volume of intraoperative blood loss, the donor liver cold ischemia time, the graft-to-recipient weight ratio were 400 minutes, 370 minutes, 390 minutes, 600 mL, 1 300 mL, 1 600 mL, 230 minutes, 152 minutes, 135 minutes, 1.2%, 0.8%, 1.1%. (2) Follow-up. B-ultrasound examination of the first, third and fourth case after liver transplantation showed that the blood flow was normal, and all the 3 cases discharged and were followed up at postoperative 1, 6 and 12 month. The liver function, the level of blood ammonia and citrulline were normal of the first, third and fourth case at postoperative 1 week. Imaging examina-tion showed normal liver morphology of the first and third case, and a transplanted liver atrophy caused by portal vein steal of the fourth case. ① The level of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), direct bilirubin (DBil) of the first case before liver transplantation, at postoperative 1 day, 2 day, 3 day, 7 day, 10 day, 6 month and 1 year were 22.8 U/L, 404.1 U/L, 355.5 U/L, 289.6 U/L, 31.0 U/L, 23.1 U/L, 42.1 U/L and 25.8 U/L, 31.5 U/L, 517.7 U/L, 327.6 U/L, 172.9 U/L, 15.9 U/L, 21.4 U/L, 47.5 U/L and 29.7 U/L, 3.8 μmol/L, 92.1 μmol/L, 87.4 μmol/L, 79.7 μmol/L, 90.1 μmol/L, 130.6 μmol/L, 33.8 μmol/L and 25.4 μmol/L, 2.3 μmol/L, 47.0 μmol/L, 44.1 μmol/L, 47.1 μmol/L, 57.4 μmol/L, 70.9 μmol/L, 24.7 μmol/L and 9.7 μmol/L, respectively. The level of citrulline and blood ammonia of the first case before and after liver transplantation were 999.0 μmol/L, 196.0 μmol/L and 14.6 μmol/L, 9.0 μmol/L, respectively. The first case was followed up for 3 years and survived without any liver transplantation related complication. ② The level of ALT, AST, TBil, DBil of the third case before liver transplantation, at postoperative 1 day, 2 day, 3 day, 7 day, 10 day, 6 month and 1 year were 21.3 U/L, 143.9 U/L, 182.0 U/L, 132.0 U/L, 17.2 U/L, 10.1 U/L, 17.6 U/L and 16.8 U/L,20.0 U/L, 291.0 U/L, 227.5 U/L, 106.4 U/L, 15.8 U/L, 10.8 U/L, 17.1 U/L and 19.4 U/L, 6.8 μmol/L, 50.9 μmol/L, 45.0 μmol/L, 34.0 μmol/L, 32.4 μmol/L, 22.3 μmol/L, 12.8 μmol/L and 14.9 μmol/L, 2.5 μmol/L, 18.4 μmol/L, 17.2 μmol/L, 14.9 μmol/L, 14.8 μmol/L, 12.1 μmol/L, 3.6 μmol/L and 4.4 μmol/L. The level of citrulline and blood ammonia of the third case after liver transplantation were 24.9 μmol/L and 16.0 μmol/L. The third case was followed up for 3 years and survived without any liver transplantation related complication. ③ The level of ALT, AST, TBil, DBil of the fourth case before liver transplantation, at postoperative 1 day, 2 day, 3 day, 7 day, 10 day, 6 month and 1 year were 35.0 U/L, 268.7 U/L, 682.0 U/L, 425.8 U/L, 57.5 U/L, 34.0 U/L, 29.4 U/L and 18.1 U/L, 37.0 U/L, 419.1 U/L, 436.2 U/L, 139.5 U/L, 35.2 U/L, 32.4 U/L, 54.7 U/L and 32.8 U/L, 7.1 μmol/L, 64.2 μmol/L, 41.4 μmol/L, 17.6 μmol/L, 34.2 μmol/L, 48.7 μmol/L, 14.1 μmol/L and 21.8 μmol/L, 2.8 μmol/L, 18.9 μmol/L, 16.1 μmol/L, 6.0 μmol/L, 14.6 μmol/L, 26.7 μmol/L, 3.9 μmol/L, 11.8 μmol/L. The level of citrulline and blood ammonia of the fourth case after liver transplantation were 8.4 μmol/L and 47.0 μmol/L. One week after surgery, the transplanted right liver of the fourth case occurred atrophy due to blood stealing from the right branch of the portal vein. B-ultrasound examination showed that the reflux of the hepatic artery and hepatic vein was unobstructed. Immunosuppressants were discontinued 3 months after operation on the fourth case and there was no complication such as rejection, bile leakage, biliary stricture, thrombosis and vascular stricture during follow-up. The fourth case died of lung metastasis 19 months after operation.Conclusion:Split domino donor auxiliary liver transplantation can be used for the treatment of metabolic liver disease and advanced hepatocellular carcinoma.

Carrier frequency of autosomal recessive disorders (BC, BLAD, FXID and CVM) in Holstein cows in Jalisco, Mexico

The hereditary autosomal recessive disorders bovine citrullinemia (BC), bovine leukocyte adhesion deficiency (BLAD), factor XI deficiency (FXID), and complex vertebral malformation (CVM) have affected dairy cattle breeding significantly around the world. This study examined the carrier frequency of BC, BLAD, FXID, and CVM autosomal recessive disorders in Bos taurus Holstein cows bred in the Altos Norte region of the state of Jalisco, Mexico. We extracted DNA from 408 random samples of peripheral blood, and then used polymerase chain reaction (PCR) to identify insertion mutations for FXID, and PCR with restriction fragment length polymorphism (PCR-RFLP) for CVM, BC and BLAD. We visualized the PCR products using agarose gel electrophoresis stained with GelRed®. We found that 100% of wild-type (N/N) allele homozygous animals for genes CD18, ASS, and FXI were free of the mutations for BLAD, BC and FXID respectively. For gene SLC35A3 we estimated total carrier frequency of 10.3% and allele frequency of 5%.(AU)

Clinical characteristics, therapy and follow-up of adult-onset type Ⅱ citrullinemia: one case report / 中华神经科杂志

Objective To analyze the diagnosis and therapy of adult-onset type Ⅱ citrullinemia (CTLN2) and compare the clinical data before and after treatment.Methods The clinical data of one patient of CTLN2 from Department of Neurology , the First Affiliated Hospital, Sun Yat-sen University on 9th December 2015 were collected.Treatment plan was formulated and adjusted by long-term follow-up.Results The patient was a 23-year-old male, complaining of recurrent mental and behavior disorders.MMSE score was 16.Blood transaminase, ammonia and citrulline were elevated and abdomen CT showed fatty liver disease.Cranial MRI showed encephaledema and SLC 25A13 gene analysis showed 851-854delGTAT homozygous mutation.Arginine was given for treatment and reduced gradually.In two years of follow-up, the patient had no longer suffered from mental and behavior disorders.Blood transaminase and ammonia remained normal.Conclusions The diagnosis of CTLN2 should be considered when a patient suffers from recurrent mental and behavior disorders , elevated blood transaminase and ammonia.Arginine along with high protein, high fat and low carbohydrates diet can improve prognosis effectively.

Citrulinemia tipo I con insuficiencia hepática recurrente en un niño / Citrullinemia type I with recurrent liver failure in a child

La citrulinemia tipo I es un desorden autosómico recesivo causado por la mutación del gen ASS1, que expresa argininosuccinato sintetasa, enzima limitante del ciclo de la urea. Las variantes clásicas están asociadas con la forma neonatal/infantil, que llevan a hiperamoniemia y a la muerte si el tratamiento no es instaurado. Los síntomas iniciales de los trastornos del ciclo de la urea incluyen deterioro neurológico con leve o moderado daño hepático. Reportamos un caso de falla hepática recurrente en un lactante con diagnóstico de citrulinemia tipo I sin compromiso neurológico grave, que fue derivado a nuestro centro para trasplante hepático. La falla hepática aguda puede ser causada por una gran variedad de desórdenes, dentro de los que se incluyen errores congénitos del metabolismo. El tratamiento adecuado de los trastornos del ciclo de la urea y, en particular, la citrulinemia I puede evitar la necesidad de un trasplante.

Citrullinemia type I is an autosomal recessive disorder caused by mutation of the gene expressing ASS1 argininosuccinate synthetase, limiting enzyme of the urea cycle. The classic variants are associated with neonatal/infantile forms that cause hyperammonemia leading to death if treatment is not established. Initial symptoms of disorders of the urea cycle include neurological impairment with mild or moderate liver damage. We report a case of recurrent liver failure in an infant diagnosed with type I citrullinemia without severe neurological involvement that was referred to our center for liver transplantation. Acute liver failure can be caused by a wide range of disorders in which inborn errors ofmetabolism are included. Appropriate treatment of disorders of the urea cycle and in particular citrullinemia I can avoid the need for a transplant.

Neonatal hyperammonemia and citrullinemia caused by argininosuccinate lyase gene mutations / 中华围产医学杂志

ObjectiveTo analyze the characteristics of neonatal hyperammonemia and citrullinemia caused by argininosuccinate lyase (ASL) gene mutations, and to have a better understanding of this disease. MethodsA neonatal patient with the onset of hyperammonemia and citrullinemia admitted to the Department of Pediatrics of Peking University First Hospital on April 2, 2014, was retrospectively studied. Peripheral blood leukocyte DNA of the patient and his parents was collected to detectASS1,ASL andSLC25A13 gene mutations. The literature related to neonatal hyperammonemia, citrullinemia and argininosuccinic aciduria was reviewed. ResultsThe baby in this case appeared lethargic, had weaker crying and food refusal since three days after birth, and analysis of blood amino acid found a marked increase in blood ammonia (1 332μmol/L) and a significant rise in citrulline (759.12μmol/L). Sanger sequencing detection revealed compound heterozygous mutations in theASL gene (c.434 A>G, c.857A>C) and this c.857A>C mutation was the first reported case in China. This case of hyperammonemia and citrullinemia was confirmed as argininosuccinic aciduria caused by ASL gene mutations. A protein-limited diet and the treatment of arginine and L-carnitine were given. His blood ammonia decreased to normal level and there was a significant improvement in physical and intellectual progress at five months old. Unfortunately, he had an intestinal infection when he was over five months old and the blood ammonia level tested in the local hospital was 480μmol/L. Gradually there was a disturbance of consciousness, then coma, and he finally died after active rescue in the local hospital.ConclusionsHyperammonemia and citrullinemia in neonates are likely to be argininosuccinic aciduria and a gene mutation test may be helpful for diagnosis.

The magnetic resonance imaging features and clinical manifestations of citrullinemia / 临床儿科杂志

Objective To investigate the brain magnetic resonance imaging (MRI) features and clinical manifesta-tions of the patients with citrullinemia, and to promote awareness of, early diagnosis of and better treatment for the disease.Methods One case with citrullinemia was reported, and other eight cases reported in the literature in nearly 14 years were reviewed.Results The case was a 15-month-old girl with type I citrullinemia diagnosed by the mutation analysis of the ASS1 gene performed in local hospital after birth. The patient was admitted to our hospital for recurrent lethargy for a year and the high level of blood ammonia (311 μmol/L, normal range 9-33 μmol/L). The blood ammonia reduced to normal on the 11th day after arginine treatment. On MRI scans, the diffusion weighted imaging (DWI) showed diffuse hyperintensity on bilateral frontal, parietal and temporal cortex, which indicated restricted diffusion due to cytotoxic edema. On the follow-up MRI after 10 day's treatment, the affected regions was similar but the intensity decreased compared to the previous scan,which accompanied by cere-bral atrophy. Eight cases in the literature were reviewed, and the clinical manifestations in these patients were lack of speciifcity, the most common features included feeding dififculties, lethargy, and vomiting. Brain MRI was performed on 7 cases, computed tomography (CT) was performed on 1 case, with the result of cytotoxic edema in 3 cases and atrophy in 2 cases.Conclusions Citrullinemia often lacks of speciifc symptoms in the early phase. Brain MRI could provide the clinician a valuable help for early diagnosis and treatment of this disease.

Citrulinemia de presentación atípica: hipo persistente: a propósito de un caso / Citrullinemia with an atypical presentation: persistent hiccups: case report

Se informa el caso de un neonato que desarrolló encefalopatía en el transcurso de los primeros tres días de vida. Presentaba hipo persistente, que evolucionó a coma profundo 72 horas después de la admisión al hospital. Los parámetros de septicemia y el análisis del líquido cefalorraquídeo (LCR) fueron normales. Tras la evaluación metabòlica, se confirmó la presencia de hiperamoniemia e hipercitrulinemia. El índice de la concentración de LCR/glicina en plasma era normal. Esto no coincidió con nuestro diagnóstico inicial de hiperglicinemia no cetósica, que suele manifestarse con hipo. Se recomienda tener en cuenta la deficiencia de ácido argininosuccínico sintetasa (ASD por su sigla en inglés; citrulinemia) de inicio neonatal en el diagnóstico diferencial de encefalopatía asociada con hipo durante el período neonatal, lo que sugiere una enzimopatía congénita.

We report an infant who developed encephalopathy within the first 3 days of life. He had persistent hiccups that progressed to deep coma 72 hours after admission. The sepsis parameters and cerebrospinal fluid examination (CSF) were normal. The metabolic evaluation confirmed hyperammonemia, and hypercitrullinemia. The ratio of CSF/plasma glycine concentration was normal. This did not agree with our initial diagnosis of nonketotic hyperglycinemia where hiccups is present more often. Neonatal onset of argininosuccinic acid synthetase deficiency (ASD; citrullinemia) should be brought in mind in the differential diagnosis of encephalopathy in association with hiccups in the neonatal period suggesting inborn errors of metabolism.

Neonatal intrahepatic cholestasis caused by Citrin deficiency / 中华实用儿科临床杂志

Neonatal intrahepatic cholestasis caused by Citrin deficiency(NICCD) is one of phenotypes of Citrin deficiency.It's an autosomal recessive disorder which was mainly seen in East Asia,including China.Case of NICCD was reported firstly by Japanese in 2001.In south area of China,the morbidity of NICCD is higher than that in north area of China.Most of the patients with NICCD has benign prognosis.Symptoms resolve within the first year of life,thus making a diagnosis difficult after this time.But few of patients will develop liver failure,even be fatal to life.Early diagnosis,regular follow-up and proper management may improve the prognosis.

The first successful live birth following preimplantation genetic diagnosis using PCR for type 1 citrullinemia

Type 1 citrullinemia (CTLN1) is an autosomal recessive inherited metabolic disorder caused by anargininosuccinicnate synthetase deficiency. The patient was a 38-year-old Korean woman who is a carrier for CTLN1 and her first baby was diagnosed with CTLN1. Preimplantation genetic diagnosis (PGD) for CTLN1 in day 3 embryos using polymerase chain reaction was performed for live birth of healthy baby who is no affected with CTLN1. One unaffected blastocyst was transferred. This resulted in a clinical pregnancy and the live birth of healthy male twin. They were confirmed to be unaffected with CTNL1 by post natal diagnosis. This is the first case report of the use of PGD for CTNL1.

Citrullinemia Type 1: Genetic Diagnosis and Prenatal Diagnosis in Subsequent Pregnancy.

Citrullinemia type 1 was diagnosed by tandem mass spectrometry in a full term male neonate who presented with an acute catastrophic collapse on the 3rd day of life. Both parents were identified to be carriers for the exon 15 p Gly390Arg mutation in the argininosuccinate synthetase gene located at chromosome 9q34.1. Chorionic villus sampling and prenatal genetic testing in the subsequent pregnancy revealed an affected fetus resulting in termination of pregnancy.

Molecular diagnosis of urea cycle disorders: Current global scenario.

Urea cycle disorders are a group of inborn error of metabolism, characterized by hyperammonemia, metabolic alkalosis and clinical features of encephalopathy. These are among the commonest types of inborn errors of metabolism with a frequency of 1 in 8,000 to 1 in 30,000 in different population. This encompasses 5 major disorders, corresponding with deficiency of each step in the urea cycle, namely ornithine transcarbamoylase (OTC) deficiency, argininosuccinate lyase (ASL) deficiency, carbamoyl phosphate synthetase (CPS) deficiency, citrullinemia and argininemia. The most important clinical presentation is neurological abnormalities. The severity of UCD is correlated to extent of hyperammonemia. Early diagnosis and treatment are essential for successful patient outcome. Various modalities of treatment have been recommended; namely, treatment aimed at reducing ammonia level, including drugs like sodium benzoate and sodium phenyl butyrate, neuroprotective strategies, low protein diet, liver transplantation and hepatocyte transplantation. Molecular diagnosis is important to identify the pathogenesis of these disorders as well as it helps in prognosis. This review intends to summarize the important aspects of molecular diagnostic studies on urea cycle disorders.

Advances of citrin deficiency / 国际儿科学杂志

Citrin deficiency,caused by mutations in SLC25A13,is an autosomal recessive genetic disorder with two age-related phenotypes:adult-oneset type Ⅱ citrullinemia and neonatal intrahepatic cholestasis.Recently,it has been found mostly in individuals of East Asian ancestry.In south China,there is a high mutation carrier frequency especially.There is still a lack of criteria for clinical or biochemical diagnosis of this disease,gene analysis is the main basis of the current diagnosis consequently.Surging number of case reports indicate that Citrin deficiency is not a self-limited disease.Early diagnosis and proper treatments may improve the prognosis.This paper focuses on the current researches in order to make further comprehensiom.

Mutation Analysis of Indian Patients with Urea Cycle Defects.

Molecular testing for a specific metabolic disorder remains the gold standard due to its high specificity and sensitivity and possibility of accurate prenatal diagnosis. We report four cases of urea cycle defect where mutational analysis of the involved genes was performed and subsequently, prenatal diagnosis could be offered to one of the family.

Clinical characteristics of adult-onset type Ⅱ citrullinemia: one case report / 中华神经科杂志

Objective To enhance clinicians' intention to the importance of early diagnosis,early therapy and follow-up of type Ⅱ citrullinemia.Methods The clinical data of one adult-onset type Ⅱ citrullinemia pedigree were collected. The gene mutation type of SLC25A13 of proband and her daughter were determined by PCR and direct gene sequencing.Results The patient was a 27 years-old female,who complained of repeated dizziness, vomiting for more than 2 years and recurrent attacks of altered consciousness for about one and a half year.An abdominal ultrasonogram,liver magnetic resonance imaging and liver histology obtained by needle biopsy all determined the liver pathological changes of liver cirrhosis.Electroencephalogram showed sharp waves. The plasma amino acid showed a marked elevation of blood citrulline.Laboratory findings revealed a highly increased concentration of plasma ammonia during every episode. Mutation analysis of the SLC25A13 gene identified a homozygote of 851del4 in the patient,and heterozygote of 851del4 in her daughter. Conclusions For adults,unexplained dizziness,vomiting,but liver function still in the compensation,especially accompanied by neuropsychologic symptoms are highly suggestive of adult-onset type Ⅱ citrullinemia.SLC25A13 gene analysis contributes to the diagnosis of this disease,avoids invasive investigations and early confirmation of this disease means long-term dietary advice,genetic counseling,medical surveillance and early preparation for liver transplantation if is necessary.

Auxiliary partial orthotopic liver transplantation for adult onset type II citrullinemia / 대한외과학회지

Adult-onset type II citrullinemia (CTLN2) is a disorder caused by an inborn error of metabolism affecting the liver. CTLN2 is an autosomal recessive disorder characterized by recurrent encephalopathy with hyperammonemia due to highly elevated plasma levels of citrulline and ammonia, caused by a deficiency of argininosuccinate synthetase in the liver. A small number of patients have undergone liver transplantation with favorable results. In Korea, the limitations of the deceased donor pool have made living donor liver transplantation a common alternative treatment option. We report the case of a patient with type II citrullinemia who was treated successfully with auxiliary partial orthotopic liver transplantation (APOLT) from a living donor. This is the first description of an APOLT for a patient with adult onset type II citrullinemia in Korea.

Novel Compound Heterozygote Mutations of the SLC25A13 Gene in an Infant with Neonatal-onset Type II Citrullinemia Detected by Newborn Mass Screening

Citrin deficiency caused by the SLC25A13 gene mutations is associated with both neonatal-onset type II citrullinemia (CTLN2), also known as neonatal intrahepatic cholestasis caused by citrin deficiency and adult-onset CTLN2. Neonatal-onset CTLN2 is an autosomal recessive disorder characterized by poor growth, intrahepatic cholestasis, and increased serum citrulline. A 16-days old infant with hyperammonemia was referred for evaluation of increased plasma citrulline diagnosed using tandem mass spectrometry. Blood amino acid analysis showed significant elevation of citrulline. Mild elevation in serum galactose levels had been found. DNA analysis of the SLC25A13 gene in this patient showed two novel compound heterozygous mutations, c.221C>T in exon4 and c.1645C in exon16 (p.[Ser74Phe]+[Gln549X]). We suggest that infants with a high serum citrulline level on a tandem mass screening test are candidates for gene analysis and blood amino acid analysis for neonatal-onset CTLN2.

Progress in mechanisms of citrin deficiency / 国际儿科学杂志

Citrin deficiency is an autosomal recessive disorder caused by mutations of the SLC25A13 gene.As a calcium binding mitochondrial aspartate glutamate carrier,Citrin plays an important role not only in the urea synthesis but NADH shuttle as well.Citrin deficiency has two phenotypes:adult-onset typeⅡcitrullinemia and neonatal intrahepatic cholestasis.Citrin deficiency is a common congenital metabolic defect first found in Japan and now is considered as a global disease.

A Novel Argininosuccinate Synthetase Gene Mutation in a Korean Family with Type I Citrullinemia

Citrullinemia type I is an urea cycle defect caused by mutations in the argininosuccinate synthetase (ASS1) gene. We report a novel argininosuccinate synthetase gene mutation in a Korean family with type I citrullinemia. Metabolic evaluation revealed significant hyperammonemia. Amino acid/acylcarnitine screening using tandem mass spectrometry showed high level of citrulline. Plasma amino acid analysis showed high level of citrulline and the urine organic acid analysis showed makedly increased level of orotic acid. To confirm diagnosis of citrullinemia we did mutation analysis of the ASS1 gene. The patient was found to have mutations of c.689G>C (p.G230A) and c.892G>A (p.E298K), which were new types of argininosuccinate synthetase gene mutation have never been reported in Korea. We report a novel case of argininosuccinate synthetase 1 gene mutation and suggest that the gene study to the family members is necessary to carry out when a patient is diagnosed as citrullinemia.