Lethal Hyperammonemia due to Ornithine Transcarbamylase Deficiency in a Patient with Severe Septic Shock / 대한구급학회지

Severe hyperammonemia can occur as a result of inherited or acquired liver enzyme defects in the urea cycle, among which ornithine transcarbamylase deficiency (OTCD) is the most common form. We report a very rare case of a 45-year-old Korean male who was admitted to the intensive care unit (ICU) due to severe septic shock with acute respiratory failure caused by Pneumocystis jiroveci pneumonia. During his ICU stay with ventilator care, the patient suffered from marked hyperammonemia (>1,700 µg/dL) with abrupt mental change leading to life-threatening cerebral edema. Despite every effort including continuous renal replacement therapy and use of a molecular adsorbent recirculating system (extracorporeal liver support-albumin dialysis) to lower his serum ammonia level, the patient was not recovered. The lethal hyperammonemia in the patient was later proven to be a manifestation of acquired liver enzyme defect known as OTCD, which is triggered by serious catabolic conditions, such as severe septic shock with acute respiratory failure.

Lethal Hyperammonemia due to Ornithine Transcarbamylase Deficiency in a Patient with Severe Septic Shock / 대한중환자의학회지

Severe hyperammonemia can occur as a result of inherited or acquired liver enzyme defects in the urea cycle, among which ornithine transcarbamylase deficiency (OTCD) is the most common form. We report a very rare case of a 45-year-old Korean male who was admitted to the intensive care unit (ICU) due to severe septic shock with acute respiratory failure caused by Pneumocystis jiroveci pneumonia. During his ICU stay with ventilator care, the patient suffered from marked hyperammonemia (>1,700 µg/dL) with abrupt mental change leading to life-threatening cerebral edema. Despite every effort including continuous renal replacement therapy and use of a molecular adsorbent recirculating system (extracorporeal liver support-albumin dialysis) to lower his serum ammonia level, the patient was not recovered. The lethal hyperammonemia in the patient was later proven to be a manifestation of acquired liver enzyme defect known as OTCD, which is triggered by serious catabolic conditions, such as severe septic shock with acute respiratory failure.

Analysis of ornithine transcarbamylase gene mutations in three boys affected with late-onset ornithine transcarbamylase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the types of OTC gene mutations in three male patients with late onset ornithine transcarbamylase deficiency (OTCD, MIM #311250).</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood leukocytes. The 10 exons and their flanking sequences of the OTC gene were amplified with polymerase chain reaction and subjected to direct DNA sequencing.</p><p><b>RESULTS</b>Based on DNA sequence analysis, all of the three patients have carried OTC gene mutations. Patients 1 and 2 were both hemizygous for mutation c.586G> A(p.D196N). A novel mutation c.800G> C(p.S267T) were confirmed in patient 3.</p><p><b>CONCLUSION</b>p.S267T mutation has affected the conserved amino acid motif of the OTC protein, and is therefore a pathogenic mutation.</p>

Analysis of clinical features, metabolic profiling and gene mutations of patients with ornithine transcarbamylase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the clinical features, metabolic profiling and gene mutations of patients with ornithine transcarbamylase deficiency (OTCD) and explore the molecular pathogenesis of OTCD in order to provide a solution for molecular diagnostics and genetic counseling.</p><p><b>METHODS</b>Clinical data of 3 neonates were analyzed. The amino acids level in blood was analyzed with mass spectrum technology. PCR was used to amplify all the 10 exons of OTC gene. The PCR products were directly sequenced to detect the mutations.</p><p><b>RESULTS</b>All of the 3 cases had neonatal onset and showed poor reaction, feeding difficulty, convulsion and neonatal infection. Citrulline levels were significantly decreased. Case 1 had a missense mutation of Y183C. Case 2 showed a missense mutation of V339G in exon 10. And a missense mutations of W332S in exon 9 was detected in case 3.</p><p><b>CONCLUSION</b>Analysis of OTC gene sequences can be used for the diagnosis of OTCD and screening of asymptomatic carriers. Mutation analysis is important for prenatal diagnosis of individuals with a positive family history and genetic counseling. The V339G and W332S mutations have been discovered for the first time. Patients with such mutations may have onset of the disease during neonatal period.</p>

Molecular diagnosis of OTC gene mutation in a Chinese family with ornithine transcarbamylase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect potential mutations of OTC gene in a male infant affected with ornithine transcarbamylase deficiency.</p><p><b>METHODS</b>Genomic DNA were isolated from peripheral blood samples of family members and 100 healthy individuals. Potential mutations of the 10 exons of OTC gene were screened with PCR and Sanger sequencing.</p><p><b>RESULTS</b>A homozygous missense mutation c.917G>C in exon 9, which results in p.R306T, was identified in the infant. Sequencing of the mother and two female members of the family indicated a heterozygous status for the same mutation. The same mutation was not found in other members of the family and 100 healthy controls.</p><p><b>CONCLUSION</b>A missense mutation c.917G>C in the OTC gene is responsible for the pathogenesis of the disease. Identification of the mutation can facilitate prenatal diagnosis and genetic counseling for the family.</p>

Clinical and gene mutation analyses of three patients with ornithine carbamoyltransferase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the clinical and genetic characteristics of three children with ornithine carbamoyltransferase deficiency(OTCD), and to provide a practical method for gene diagnosis and genetic counseling of the disease.</p><p><b>METHODS</b>All exons of the ornithine carbamoyltransferase (OTC) gene were screened by polymerase chain reaction-DNA direct sequencing in the three OTCD patients.</p><p><b>RESULTS</b>One patient firstly presented as vomiting at 6 month of age. A missense mutation of T262I was detected. His mother had the same mutation without any clinical symptoms. The second patient presented as restlessness, and had a missense mutation of R277W. Gene analysis of his parents was not available. The third patient presented as neonatal lethargy, harbored a missense mutation of I172M. His mother had the same mutation without any clinical symptoms.</p><p><b>CONCLUSION</b>Gene mutation analysis is a feasible way for diagnosing OTCD. Patients with I172M mutation present symptom early, while those with T262I and R277W mutations manifest symptoms later. Gene mutation analysis will be important for asymptomatic and prenatal diagnosis and genetic counseling.</p>

Analysis of clinical features, biochemical analysis and gene mutations in one Chinese pedigree with neonatal-onset ornithine transcarbamylase deficiency / 中华儿科杂志

<p><b>OBJECTIVE</b>This study aimed at understanding clinical features, biochemistry and gene mutation in one Chinese pedigree which had a neonatal-onset ornithine transcarbamylase deficiency (OTCD) boy, and exploring the significance of ornithine transcarbamylase analysis in prenatal diagnosis.</p><p><b>METHOD</b>The clinical and biochemical data of one case were analyzed. The amino acids in blood and organic acids in urine were analyzed by mass spectrum technology. The OTC gene mutation was detected using polymerase chain reaction (PCR) and DNA direct sequencing for the case, his parents and the fetus amniocyte and her blood after birth.</p><p><b>RESULT</b>The age of onset was 3 days after birth, he began to have poor reaction, difficulty to feed, high blood ammonia, infection, slight metabolic acidosis, which were consistent with the clinical diagnosis of urea cycle disorders. The boy died at the age of 9 days. Citrulline of blood was detected twice, and were 0.86 µm and 1.06 µm, respectively. The orotic acid was elevated (124 µm/M Creatinine), and urine lactic acid was significantly elevated. The citrulline and orotic acid in his parents and their second baby were normal in DBS and urine. One nonsense mutation in the OTC gene was found at the exon 9 (C. 958 C > T) and his mother was the heterozygote, which caused an arginine to terminate the code at position 320 of the protein (R320X). Two other mutations were also detected at intron 9 (C.1005 + 132 InsT) and intron 5 (C.542 + 134 G > G/A). But the analysis of his father's DNA, the fetus amniocyte and her blood was normal.</p><p><b>CONCLUSION</b>The mutation of C. 958 C > T in OTC gene may occur during neonatal period. This mutation would result in a very severe symptom, even die suddenly several days after birth, if it was a boy. It needs more researches to discuss whether the C.1005 + 132 InsT in intron 9 and C.542 + 134 G > G/A in intron 5 were associated with the neonatal-onset OTCD. The DNA analysis of OTC gene could be utilized for the prenatal diagnosis.</p>

Acute treatment of hyperammonemia by continuous renal replacement therapy in a newborn patient with ornithine transcarbamylase deficiency / 소아과

Ornithine transcarbamylase (OTC) deficiency is well known as the most common inherited disorder of the urea cycle, and 1 of the most common causes of hyperammonemia in newborns. We experienced a case of a 3-day-old boy with OTC deficiency who appeared healthy in the first 2 days of life but developed lethargy and seizure soon afterwards. His serum ammonia level was measured as >1700 microg/dL (range, 0 to 45 microg/dL). Continuous renal replacement therapy (CRRT) in the mode of continuous venovenous hemodiafiltration was immediately applied to correct the raised ammonia level. No seizure occurred after the elevated ammonia level was reduced. Therefore, CRRT should be included as 1 of the treatment modalities for newborns with inborn errors of metabolism, especially hyperammonemia. Here, we report 1 case of successful treatment of hyperammonemia by CRRT in a neonate with OTC deficiency.

The relationship of CPS-I, OCT and hepatic encephalopathy / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the role of carbamyl phosphate I (CPS-I)and ornithine transcarbamoylase (OCT) levels in cirrhosis patients with and without hepatic encephalopathy, and to analyze the correlations between CPS-Iand OCT with the development of hepatic encephalopathy.</p><p><b>METHODS</b>CPS-I, OCT, plasma ammonia and liver function of 95 cirrhosis patients with hepatic encephalopathy and 25 cirrhosis patients without hepatic encephalopathy in our hospital from January 2008 to December 2009 were analyzed. 60 healthy controls were recruited in the control group. The differences of serum CPS-I, OCT levels among the cirrhosis patients with and without hepatic encephalopathy and the healthy controls were analyzed; the correlations of CPS-I, OCT levels with plasma ammonia and total protein in cirrhosis patients,and the correlations of CPS-I, OCT levels with Child-Pugh classification of cirrhosis symptom severity in cirrhosis were analyzed. the clinical characteristics between patients who had HE and no HE with chi-square tests were compared. Comparisons of CPS-I, OCT levels across patients based on the Child-Pugh classification were performed with One-Way ANOVA and Student-Newman-Keuls, correlation of CPS-I, OCT with other indicators were performed with Pearson correlation analysis.</p><p><b>RESULTS</b>Serum CPS-I and OCT levels in cirrhosis patients with hepatic encephalopathy were (143.3+/-48.5) U/L, (297.0+/-102.6) is multiplied by 10 U/L, which were lower than that in cirrhosis patients without hepatic encephalopathy (180.3+/-51.5) U/L, (351.8+/-109.0) is multiplied by 10 U/L (t = 2.53, t = 2.78, P < 0.01). Compared with healthy controls, serum CPS-I and OCT levels in cirrhosis patients with and without hepatic encephalopathy were all lower (t = 3.21, t = 4.16, t = 2.12, t = 3.15, P < 0.05). CPS-I was correlated with OCT, (r = 0.946, P < 0.05); CPS-I and OCT were negatively correlated with ALT and AST (r = -0.284, r = -0.239, r = -0.303, r = -0.322, P < 0.05). Additionally, CPS-I and OCT levels were negatively correlated with the Child-Pugh classification in Cirrhosis (F = 10.13, F = 20.28, P < 0.01).</p><p><b>CONCLUSION</b>The serum CPS-I and COT levels were important factors affecting plasma ammonia in patients with cirrhosis and played an important role in the development of hepatic encephalopathy.</p>

A Case of Molecular Diagnosis of Ornithine Transcarbamylase Deficiency / 영남의대학술지

Ornithine transcarbamylase (OTC) deficiency is the most common inborn error of urea cycle metabolism; it is inherited in an X-linked manner. The OTC catalyzes the third step of the urea cycle, the conversion of ornithine and carbamyl phosphate to citrulline. Deficiency of OTC leads to the accumulation of ammonia, causing neurological deficits. In most affected hemizygote males, OTC deficiency manifests as hyperammonemic coma that often leads to death in the newborn period, and those who recover from the coma may be neurologically impaired due to the sequelae of the hyperammonemic encephalopathy. In some, late-onset manifestations develop. We report a male neonate with early onset OT deficiency that had apnea and was comatous. On mutation analysis using DNA sequencing after polymerase chain reaction (PCR) amplification of the 10 exons, deletions of 10 bases in codon 285, causing a frame shift was detected in exon 8. The mother and a sister were diagnosed as female carriers. Therefore, genetic counseling and the risk assessment could be provided to the family.

Preimplantation Genetic Diagnosis for Ornithine Transcarbamylase Deficiency by Simultaneous Analysis of Duplex-nested PCR and Fluorescence In Situ Hybridization: A Case Report

Ornithine transcarbamylase (OTC) deficiency is an X-linked co-dominant disorder. A couple, with a previous history of a neonatal death and a therapeutical termination due to OTC deficiency, was referred to our center for preimplantation genetic diagnosis (PGD). The female partner has a nonsense mutation in the exon 9 of the OTC gene (R320X). We carried out nested polymerase chain reaction (PCR) for R320X mutation and fluorescence in situ hybridization (FISH) for aneuploidy screening. Among a total of 11 embryos, two blastomeres per embryo from 9 embryos were biopsied and analyzed by duplex-nested PCR and FISH, and one blastomere per embryo from 2 embryos by only duplex-nested PCR. As a result of PCR and restriction fragment length polymorphism analysis, four embryos were diagnosed as unaffected embryos having the normal OTC gene. Among these embryos, only one embryo was confirmed as euploidy for chromosome X, Y and 18 by FISH analysis. A single normal embryo was transferred to the mother, yielding an unaffected pregnancy and birth of a healthy boy. Based on our results, PCR for mutation loci and FISH for aneuploidy screening with two blastomeres from an embryo could provide higher accuracy for the selection of genetically and chromosomally normal embryos in the PGD for single gene defects.

Reliability of the Single Cell PCR analysis for Preimplantation Genetic Diagnosis of Single Gene Disorders / 대한불임학회지

No abstract available.

Biochemical responses of two Erythrinidae fish to environmental ammonia

A forma não ionizada da amônia é muito tóxica a vários organismos aquáticos, sendo particularmente importante em muitos aspectos da biologia dos peixes. Um amplo grupo de estratégias para enfrentar os estressores ambientais pode ser observado nos organismos vivos. Dentre estas, as respostas aos estressores químicos são bem estudadas. O presente trabalho compara respostas bioquímicas de duas espécies evolutivamente próximas Hoplias malabaricus e Hoplerythrinus unitaeniatus, expostas à amônia ambiental. Peixes adultos foram submetidos a 1.0 mg/L de cloreto de amônio por 24 horas e foram determinados os níveis plasmáticos de amônia e uréia. As atividades das enzimas do COU, OCT e ARG e a enzima acessória GS foram quantificadas em extrato de fígado e são expressas em mmol/min/mg de tecido úmido. Foi observado em H. malabaricus, exposto a 1,0 mg/L de cloreto de amônio, aumento (p < 0,05) nas enzimas: GS, de 1,14 para 2,43; OCT, de 0,81 para 1,72; ARG, de 3,15 para 4,23; na amônia plasmática, de 0,95 para 1,42 mmol/L, e na uréia plasmática, de 0,82 para 1,53. A GS de H. malabaricus aumentou de 1,43 para 1,84, todavia, OCT, ARG e uréia plasmática não variaram. Esses dados mostram que ambas as espécies, taxonomicamente próximas, respondem distintamente ao mesmo estressor ambiental.

Successful Preimplantation Genetic Diagnosis for Ornithine Transcarbamylase Deficiency, Junctional Epidermolysis Bullosa and Lactic Acidosis Using Duplex Nested PCR: Delivery of Healthy Baby by Specific Preimplantation Genetic Diagnosis for Ornithine Tran / 대한산부인과학회잡지

OBJECTIVE: Preimplantation genetic diagnosis (PGD) is reserved for couples with a risk of transmitting a serious and incurable disease, and hence avoids the undesirable therapeutic abortion. Herein, we report the result of PGD to carriers at risk of transmitting ornithine transcarbamylase (OTC) deficiency, junctional epidermolysis bullosa (EB) and lactic acidosis (LA) due to defect of pyruvate dehydrogenase alpha1 gene, respectively. METHODS: The ovarian stimulation, oocyte retrieval and ICSI procedure were undergone by conventional protocols. PGD for single gene disorders was carried out after biopsy of one or two blastomeres from the embryos on the third day. We performed the duplex nested PCR of the simultaneous amplification for the causative mutation loci as well as the SRY gene on Y chromosome in case of OTC deficiency and LA. Two different mutation loci of ITGB4 gene in EB case were amplified by the same protocol. The PCR products were analyzed by agarose gel electrophoresis, restriction fragment length polymorphism analysis or direct DNA sequencing. RESULTS: A total of 26 embryos were analyzed by duplex nested PCR. One or two blastomeres were biopsied, and successful diagnosis rate of PGD with PCR was 92.3% (24/26). There was no contamination in all PCR samples of negative controls (n=67). Five embryos (19.2%) were diagnosed as normal embryos, which were transferred to the mothers' uterus in each cases. In OTC deficiency case, singleton pregnancy was established. At 17 weeks of gestation, genetic normality of OTC gene in fetus was confirmed by amniocentesis. A healthy baby was successfully delivered at 36 weeks of gestation in OTC deficiency case. Unfortunately, pregnancies were not achievement in cases of EB and LA. CONCLUSION: This is the first report in Korea that healthy baby was born after specific PGD for OTC deficiency. Our results demonstrate that duplex nested PCR for single cell is an efficient method in identifying the gender and single gene mutation or two different mutation loci, simultaneously. This PGD procedure could provide normal healthy baby to the couple with a high risk of transmitting genetic diseases.

Different biochemical strategies of two Neotropical fish to cope with the impairment of nitrogen excretion during air exposure

The exposure of fish to air is normally expected to interfere with the nitrogen excretion process. Hoplias malabaricus and Hoplerythrinus unitaeniatus, two teleost species, display distinct behaviors in response to decreases in natural reservoir water levels, although they may employ similar biochemical strategies. To investigate this point, plasma levels of ammonia, urea, uric acid, and the two urea cycle enzymes, ornithine carbamoyl transferase (OCT) and arginase (ARG), as well as glutamine synthetase (GS) were determined for both species after exposure to air. Plasma ammonia increased gradually during exposure to air, but only H. malabaricus showed increased concentrations of urea. Plasma uric acid remained very low in both fish. Enzymatic activities (mean ± SD, æmol min-1 g protein-1) of H. malabaricus showed significant increases (P<0.05, N = 6) in OCT from 0.84 ± 0.05 to 1.42 ± 0.03, in ARG from 8.07 ± 0.47 to 9.97 ± 0.53 and in GS from 1.15 ± 0.03 to 2.39 ± 0.04. The OCT and ARG enzymes remained constant in H. unitaeniatus (N = 6), but GS increased from 1.49 ± 0.02 to 2.06 ± 0.03. Although these species are very closely related and share the same environment, their biochemical strategies in response to exposure to air or to increased plasma ammonia are different

Molecular characterization of a new mutation E122G of human ornithine transcarbamylase gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the molecular basis of late onset ornithine transcarbamylase (OTC) deficiency in a Chinese family of Han nationality and the exon sequences of OTC gene of this patient.</p><p><b>METHODS</b>Polymerase chain reaction-single strand conformation polymorphism and direct sequencing were used to identify the mutation type.</p><p><b>RESULTS</b>A missense mutation E122G in the conserved residue of exon 4 was identified which is unreported before.</p><p><b>CONCLUSION</b>The E122G mutation in human OTC gene may cause late onset OTC deficiency.</p>

Urea cycle disorders in Thai infants: a report of 5 cases.

Urea Cycle Disorders (UCD) is an inborn error of urea synthesis in which ammonium and other nitrogenous precursors of urea accumulate leading to episodic coma and a high mortality rate. Therapy with peritoneal dialysis, essential amino acids or their nitrogen-free analogues has increased survival. The authors report 5 cases of urea cycle disorders, all of whom developed and were rescued from hyperammonemic coma. However, the eventual outcome was quite variable. Argininosuccinate lyase deficiency (ALD) Case 1. A 2 month old male infant, a product of a consanguineous marriage (Suphanburi province); developed poor feeding on day 7, lethargy, convulsion, hepatomegaly and respiratory alkalosis leading to respiratory failure and coma. Hyperammonemia, elevation of glutamic acid and argininosuccinic acid and its anhydrides confirmed the diagnosis of ALD. He is now 9 years old and severely retarded. Case 2. A male infant with history of lethargy, poor feeding on day 3, treated as sepsis and required respiratory support for 6 days; subsequently readmitted at age 2 weeks with vomitting, lethargy, seizure activity and hyperammonemia, and was treated by a local pediatrician in Songkhla province. There was a history of parental consanguinity and he was referred to Siriraj Hospital on day 64 with severe essential amino acid deficiency and acrodermatitis enteropathica with markedly elevated plasma citrulline level. In spite of aggressive treatment; the patient developed sepsis and he expired on day 78. Ornithine transcarbamylase deficiency (OTC) Case 3. An eleven-month-old male infant, the product of a non-consanguineous marriage, developed neonatal onset of hyperammonemia on day 5 after poor feeding, lethargy, hypothermia, seizure, apnea and coma. He was rescued from neonatal hyperammonemic coma on day 9 after aggressive treatment, but expired at eleven months of age after overwhelming sepsis. Case 4. A male infant, sibling of case 3 was referred to Siriraj Hospital on day 8 with hyperammonemia and coma. In spite of intensive genetic counseling given after the birth of their first child with OTC, the couple chose to have another baby without informing any physician. The baby developed vomiting and lethargy on day 2; subsequently hyperammonemia was noted. In spite of aggressive treatment given; hepatic dysfunction, renal failure and disseminated intravascular coagulation defects occurred on day 15. He expired on day 18 after parental permission for discontinuation of all treatment. Argininosuccinate synthetase deficiency (ASS) or Citrullinemia. Case 5. A seven week old female infant, the product of a consanguineous marriage and of Pakistani ethnic origin; developed intermittent vomiting from day 6. Initial diagnoses included ruminations, sepsis and pyloric stenosis for which she was operated on (day 30); however, vomiting continued; subsequently seizures, hyperammonemic coma developed and she was rescued from hyperammonemic coma within 30 hours. Significant elevations of citrulline and L-glutamine were demonstrated. She was discharged in excellent condition to her home in Dubai, the United Arab Emirates.

A Case of Ornithine Transcarbamylase (OTC) Deficiency

OTC deficiency is an X-linked disorder in which the synthesis of urea is impaired. OTC catalyzes the synthesis of citrulline from carbamyl phosphate and ornithine. Complete or partial deficiencies of this enzyme may lead to Reye syndrome like picture such as encephalopathy, hepatic dysfunction, hyperammonemia, etc. We recently had a case that was presented as recurrent Reye syndrome, and was effectively treated with hemodialysis, arginine, sodium benzoate, etc. This report describes an experience in treating this condition with review of available literature.

Deficiência de ornitina transcarbamilase: diagnóstico neonatal / Ornithine transcarbamylase deficiency: Neonatal diagnostic

Objetivo: Alertar os pediatras para a deficiência de enzimas do ciclo da uréia. Essa patologia deve ser lembrada, pois o prognóstico do recém-nascido está diretamente relacionado com a precocidade do diagnóstico e a instituiçäo de uma terapêutica adequada. Método: Apresentamos um paciente que, após 48 horas de vida, iniciou com quadro de sonolência, letargia, vômitos e convulsäo, tendo-se pensado, inicialmente, em sepsis neonatal. Após excluído esse diagnóstico, foi diagnosticada deficiência de ornitina transcarbamilase (OTC). Resultado: O paciente foi tratado e acompanhado até a idade de um ano, quando foi submetido ao transplante hepático com boa evoluçäo e controle da doença. Conclusäo: A deficiência de ornitina transcarbamilase (OTC), é rara, porém muito grave. O recém-nascido que apresentar um quadro clínico semelhante ao de recém-nascido séptico, porém sem contexto infeccioso, deve ser investigado para essa patologia, pois o prognóstico está diretamente relacionado com a rapidez do diagnóstico e do tratamento