Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adult-onset type II citrullinemia (CTLN2) is an autosomal recessive disease caused by mutations in SLC25A13, the gene encoding the mitochondrial aspartate/glutamate carrier citrin. The absence of citrin leads to a liver-specific, quantitative decrease of argininosuccinate synthetase (ASS), causing hyperammonemia and citrullinemia. To investigate the physiological role of citrin and the development of CTLN2, an Slc25a13-knockout (also known as Ctrn-deficient) mouse model was created. The resulting Ctrn-/- mice were devoid of Slc25a13 mRNA and citrin protein. Liver mitochondrial assays revealed markedly decreased activities in aspartate transport and the malate-aspartate shuttle. Liver perfusion also demonstrated deficits in ureogenesis from ammonia, gluconeogenesis from lactate, and an increase in the lactate-to-pyruvate ratio within hepatocytes. Surprisingly, Ctrn-/- mice up to 1 year of age failed to show CTLN2-like symptoms due to normal hepatic ASS activity. Serological measures of glucose, amino acid, and ammonia metabolism also showed no significant alterations. Nitrogen-loading treatments produced only minor changes in the hepatic ammonia and amino acid levels. These results suggest that citrin deficiency alone may not be sufficient to produce a CTLN2-like phenotype in mice. These observations are compatible, however, with the variable age of onset, incomplete penetrance, and strong ethnic bias seen in CTLN2 where additional environmental and/or genetic triggers are now suspected.
Mol Cell Biol 2004 Jan
PMID:Slc25a13-knockout mice harbor metabolic deficits but fail to display hallmarks of adult-onset type II citrullinemia. 1470 27

Citrin is a mitochondrial aspartate glutamate carrier primarily expressed in the liver, heart, and kidney. We found that adult-onset type II citrullinemia is caused by mutations in the SLC25A13 gene that encodes for citrin. In this report, we describe the frequency of SLC25A13 mutations, the roles of citrin as a member of the urea cycle and as a member of the malate-aspartate shuttle, the relationship between its functions and symptoms of citrin deficiency, and therapeutic issues.
Mol Genet Metab 2004 Apr
PMID:Adult-onset type II citrullinemia and idiopathic neonatal hepatitis caused by citrin deficiency: involvement of the aspartate glutamate carrier for urea synthesis and maintenance of the urea cycle. 1505 Sep 70

A deficiency of citrin, which is encoded by the SLC25A13 gene, causes both adult-onset type II citrullinemia (CTLN2) and neonatal intrahepatic cholestasis (NICCD). We analyzed 16 patients with NICCD to clarify the clinical features of the disease. Severe intrahepatic cholestasis with fatty liver was the most common symptom, but the accompanying clinical features were variable, namely; suspected cases of neonatal hepatitis or biliary atresia, positive results from newborn screening, tyrosinemia, failure to thrive, hemolytic anemia, bleeding tendencies and ketotic hypoglycemia. Laboratory data showed elevated serum bile acid levels, hypoproteinemia, low levels of vitamin K-dependent coagulation factors, and hypergalactosemia. Hypercitrullinemia was detected in 11 out of 15 patients examined. Most of the patients were given a lactose-free and/or medium chain triglycerides-enriched formula and lipid-soluble vitamins. The prognosis of the 16 patients is going fairy well at present, but we should observe these patients carefully to see if they manifest any symptom of CTLN2 in the future.
Mol Genet Metab 2004 Nov
PMID:Clinical heterogeneity of neonatal intrahepatic cholestasis caused by citrin deficiency: case reports from 16 patients. 1554 92

A 16-month old boy was referred to our hospital for evaluation of recurrent generalized tonic clonic seizures. Metabolic evaluation revealed significant hyperammonemia (1,112 microg/dl). Amino acid/acylcarnitine screening using tandem mass spectrometry showed markedly increased plasma levels of citrulline (1,350 microM/l) with undetectable levels of arginine and arginosuccinic acid. Urinary excretion of citrulline was markedly increased (38,617 microM/g creatinine). Brain MRI findings showed diffuse high-signal intensity lesions, that involved gray and white matter in both frontal lobes and insula with edematous changes; these findings were consistent with the acute stage of citrullinemia (CTLN). Mutation analysis of the argininosuccinate synthetase (ASS) gene, in this patient, showed a Gly324Ser mutation in exon 13, and a 67-bp duplication mutation in exon 15 (c.1128-6_1188dup67). The patient was confirmed as having late-onset CTLN1 and treated with anticonvulsants, lactulose enema, protein restricted diet and arginine. Here we describe a case of late-onset CTLN1 in a patient by biochemical analyses and ASS gene mutation confirmation. This is the first report of a Korean patient with late-onset CTLN1 confirmed by ASS gene mutation identification.
J Biochem Mol Biol 2006 Jul 31
PMID:Characterization of late-onset citrullinemia 1 in a Korean patient: confirmation by argininosuccinate synthetase gene mutation analysis. 1688 83

Citrin deficiency induces two clinical features; namely neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and adult-onset type II citrullinemia. Hypercitrullinemia is the most characteristic feature, whereas there are non-citrullinemic individuals. Diagnosis of citrin deficiency is performed by genetic analysis, although the 12 known mutations in the alleles are not detected in about 15% of cases. Thus, we aimed to examine citrin protein in lymphocytes isolated from peripheral blood as an alternative diagnostic method. We examined 38 children having an episode of cholestatic liver dysfunction, 8 heterozygotes, and 11 healthy individuals. All subjects were evaluated for citrin protein by Western blotting and for the 12 known mutations by gene analysis. Citrin protein was detected in 15 of 38 children with cholestatic liver dysfunction. Fourteen of them were negative for 12 known mutations in both alleles, whereas one patient was found to have a known mutation in one allele. Citrin protein was absent in 23 of the 38 patients. Among these 23, gene analysis diagnosed citrin deficiency in 19, whereas 2 patients were later revealed to be NICCD with novel mutations. In the remaining 2 patients, who exhibit the clinical features of NICCD, a known mutation was detected in one allele but no mutation was identified in another allele. Citrin protein was also detected in the 8 heterozygotes and 11 healthy individuals. We disclosed that citrin was deficient in lymphocytes among patients with citrin deficiency. Analysis of citrin is useful to diagnose citrin deficiency even in patients without known mutations or hypercitrullinemia.
Mol Genet Metab 2007 Jan
PMID:Novel diagnostic approach to citrin deficiency: analysis of citrin protein in lymphocytes. 1709 49

Citrin deficiency resulting from mutations of the SLC25A13 gene is associated with two major clinical phenotypes; neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and adult-onset type 2 citrullinemia (CTLN2). In Korea, 6 cases of citrin deficiency were diagnosed based on biochemical and molecular findings. Four NICCD patients (2 boys and 2 girls) presented high citrulline levels on a newborn screening test or neonatal cholestasis. They were associated with conjugated hyperbilirubinemia, elevated liver enzymes, hypoalbuminemia, mild hyperammonemia, elevated citrulline, methionine and threonine. All of the hepatic manifestations were resolved spontaneously at the age of 5-9 months. Mutation analysis identified them as compound heterozygotes carrying each of the c.851del4, IVS11+1G>A, IVS13+1G>A, G393S, and IVS16ins3kb mutant alleles. Two adult male CTLN2 patients were identified. They were aged 24 and 37 years, and presented sudden loss of consciousness, hyperammonemia and citrullinemia. They were compound heterozygotes with IVS13+1G>A and IVS16ins3kb, and with c.851del4 and IVS11+1G>A mutant alleles. This report describes the clinical characteristics, biochemical findings and molecular analysis of the SLC25A13 gene of patients with citrin deficiency in Korea.
Int J Mol Med 2007 Dec
PMID:Six cases of citrin deficiency in Korea. 1798 87

Inherited urea cycle disorders comprise eight disorders (UCD), each caused by a deficiency of one of the proteins that is essential for ureagenesis. We report on a cross-sectional investigation to determine clinical and laboratory characteristics of patients with UCD in the United States. The data used for the analysis was collected at the time of enrollment of individuals with inherited UCD into a longitudinal observation study. The study has been conducted by the Urea Cycle Disorders Consortium within the Rare Diseases Clinical Research Network (RDCRN) funded by the National Institutes of Health. One-hundred eighty-three patients were enrolled into the study. Ornithine transcarbamylase (OTC) deficiency was the most frequent disorder (55%), followed by argininosuccinic aciduria (16%) and citrullinemia (14%). Seventy-nine percent of the participants were white (16% Latinos), and 6% were African American. Intellectual and developmental disabilities were reported in 39% with learning disabilities (35%) and half had abnormal neurological examination. Sixty-three percent were on a protein restricted diet, 37% were on Na-phenylbutyrate and 5% were on Na-benzoate. Forty-five percent of OTC deficient patients were on L-citrulline, while most patients with citrullinemia (58%) and argininosuccinic aciduria (79%) were on L-arginine. Plasma levels of branched-chain amino acids were reduced in patients treated with ammonia scavenger drugs. Plasma glutamine levels were higher in proximal UCD and in neonatal type disease. The RDCRN allows comprehensive analyses of rare inherited UCD, their frequencies and current medical practices.
Mol Genet Metab 2008 Aug
PMID:Cross-sectional multicenter study of patients with urea cycle disorders in the United States. 1856 31

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) shows diverse metabolic abnormalities such as urea cycle dysfunction together with citrullinemia, galactosemia, and suppressed gluconeogenesis. Such abnormalities apparently resolve during the first year of life. However, metabolic profiles of the silent period remain unknown. We analyzed oxidative stress markers and profiles of amino acids, carbohydrates, and lipids in 20 asymptomatic children with aspartate/glutamate carrier isoform 2-citrin-deficiency aged 1-10 years, for whom tests showed normal liver function. Despite normal plasma ammonia levels, the affected children showed higher blood levels of ornithine (p<0.001) and citrulline (p<0.01)--amino acids involved in the urea cycle--than healthy children. Blood levels of nitrite/nitrate, metabolites of nitric oxide (NO), and asymmetric dimethylarginine inhibiting NO production from arginine were not different between these two groups. Blood glucose, galactose, pyruvate, and lactate levels after 4-5h fasting were not different between these groups, but the affected group showed a significantly higher lactate to pyruvate ratio. Low-density and high-density lipoprotein cholesterol levels in the affected group were 1.5 times higher than those in the controls. Plasma oxidized low-density lipoprotein apparently increased in the affected children; their levels of urinary oxidative stress markers such as 8-hydroxy-2'-deoxyguanosine and acrolein-lysine were significantly higher than those in the controls. Results of this study showed, even during the silent period, sustained hypercitrullinemia, hypercholesterolemia, and augmented oxidative stress in children with citrin deficiency.
Mol Genet Metab 2009 May
PMID:Sustaining hypercitrullinemia, hypercholesterolemia and augmented oxidative stress in Japanese children with aspartate/glutamate carrier isoform 2-citrin-deficiency even during the silent period. 1923 6

Citrullinemia type I (CTLN1) is a urea cycle disorder which typically presents in the neonatal period or infancy with hyperammonemia and concurrent neurologic deterioration. We report a 15-month-old female with CTLN1 who presented with encephalopathy and seizures with hyperammonemia requiring emergency treatment. Although there was a rapid resolution of her hyperammonemia, she developed fulminant liver failure. The severe increase of transaminases (aspartate aminotransferase and alanine aminotransferase levels peaking at 19,794 UI/L and 19,938 UI/L, respectively) and concurrent disturbances in her hepatic synthetic functions led to the consideration of a liver transplantation. However, there was a normalization of her liver function tests over the course of weeks with supportive therapy alone. Molecular analysis of the ASS1 gene confirmed the diagnosis of CTLN1 by revealing the known mutation c.1087C>T (p.R363W) on the paternal allele and an intronic nucleotide exchange leading to an insertion of 69 bp on the transcript resulting in a frameshift and premature stop of translation on the maternal allele. We also briefly report another case of CTLN1 where liver failure was a prominent feature of the presentation. Fulminant liver failure has been described with a variety of other urea cycle disorders, but has been described in infantile onset presentation of CTLN1 in only two other cases recently. Our observation suggests that in some cases of CTLN1 with acute liver failure, emergency intervention such as transplantation is not warranted despite evidence of severe hepatotoxicity.
Mol Genet Metab 2011 Apr
PMID:Transient fulminant liver failure as an initial presentation in citrullinemia type I. 2122 27

Citrin is a liver-type aspartate/glutamate carrier (AGC) encoded by the gene SLC25A13. Two phenotypes for human citrin deficiency have been described, namely the adult-onset citrullinemia type II (CTLN2) and the neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). However, citrin deficiency currently remains a perplexing and poorly recognized disorder. In particular, description of post-NICCD clinical presentations before CTLN2 onset is rather limited. Analysis of SLC25A13 mutations, identification of dysmorphic erythrocytes, hepatobiliary scintigraphic imaging and investigation of post-NICCD clinical presentations were performed in a citrin-deficient cohort comprised of 51 cases of children diagnosed with citrin deficiency in a Chinese pediatric center. Twelve SLC25A13 mutations were detected in this cohort, including the novel V411M and G283X mutations. Among the 51 citrin-deficient subjects, 7 cases had echinocytosis, which was associated with more severe biochemical abnormalities. Delayed hepatic discharge and bile duct/bowel visualization were common scintigraphic findings. Moreover, 9 of the 34 post-NICCD cases demonstrated concurrent failure to thrive and dyslipidemia, constituting a clinical phenotype different from NICCD and CTLN2. The novel mutations, echinocytosis, hepatobiliary scintigraphic features and the novel clinical phenotype in this study expanded the genotypic and phenotypic spectrum of citrin deficiency, and challenge the traditionally-assumed 'apparently healthy' period after the NICCD state for this disease entity.
Int J Mol Med 2011 Jul
PMID:Genotypic and phenotypic features of citrin deficiency: five-year experience in a Chinese pediatric center. 2142 15


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