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Tavoulari S, Lacabanne D, Thangaratnarajah C, Kunji ERS. Pathogenic variants of the mitochondrial aspartate/glutamate carrier causing citrin deficiency. Trends Endocrinol Metab 2022; 33:539-553. [PMID: 35725541 PMCID: PMC7614230 DOI: 10.1016/j.tem.2022.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/26/2022] [Accepted: 05/19/2022] [Indexed: 12/22/2022]
Abstract
Citrin deficiency is a pan-ethnic and highly prevalent mitochondrial disease with three different stages: neonatal intrahepatic cholestasis (NICCD), a relatively mild adaptation stage, and type II citrullinemia in adulthood (CTLN2). The cause is the absence or dysfunction of the calcium-regulated mitochondrial aspartate/glutamate carrier 2 (AGC2/SLC25A13), also called citrin, which imports glutamate into the mitochondrial matrix and exports aspartate to the cytosol. In citrin deficiency, these missing transport steps lead to impairment of the malate-aspartate shuttle, gluconeogenesis, amino acid homeostasis, and the urea cycle. In this review, we describe the geological spread and occurrence of citrin deficiency, the metabolic consequences and use our current knowledge of the structure to predict the impact of the known pathogenic mutations on the calcium-regulatory and transport mechanism of citrin.
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Affiliation(s)
- Sotiria Tavoulari
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Denis Lacabanne
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Chancievan Thangaratnarajah
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK.
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Citrin deficiency mimicking mitochondrial depletion syndrome. BMC Pediatr 2020; 20:518. [PMID: 33176737 PMCID: PMC7659096 DOI: 10.1186/s12887-020-02409-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/30/2020] [Indexed: 11/10/2022] Open
Abstract
Background Neonatal intrahepatic cholestasis caused by citrin deficiency (CD) is a rare inborn error of metabolism due to variants in the SLC25A13 gene encoding the calcium-binding protein citrin. Citrin is an aspartate-glutamate carrier located within the inner mitochondrial membrane. Case presentation We report on two siblings of Romanian-Vietnamese ancestry with citrin deficiency. Patient 1 is a female who presented at age 8 weeks with cholestasis, elevated lactate levels and recurrent severe hypoglycemia. Diagnosis was made by whole exome sequencing and revealed compound heterozygosity for the frameshift variant c.852_855del, p.Met285Profs*2 and a novel deletion c.(69 + 1_70–1)_(212 + 1_231–1)del in SLC25A13. The girl responded well to dietary treatment with a lactose-free, MCT-enriched formula. Her younger brother (Patient 2) was born 1 year later and also found to be carrying the same gene variants. Dietary treatment from birth was able to completely prevent clinical manifestation until his current age of 4.5 months. Conclusions As CD is a well-treatable disorder it should be ruled out early in the differential diagnosis of neonatal cholestasis. Due to the combination of hepatopathy, lactic acidosis and recurrent hypoglycemia the clinical presentation of CD may resemble hepatic mitochondrial depletion syndrome.
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AGC2 (Citrin) Deficiency-From Recognition of the Disease till Construction of Therapeutic Procedures. Biomolecules 2020; 10:biom10081100. [PMID: 32722104 PMCID: PMC7465890 DOI: 10.3390/biom10081100] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/17/2020] [Accepted: 07/19/2020] [Indexed: 12/16/2022] Open
Abstract
Can you imagine a disease in which intake of an excess amount of sugars or carbohydrates causes hyperammonemia? It is hard to imagine the intake causing hyperammonemia. AGC2 or citrin deficiency shows their symptoms following sugar/carbohydrates intake excess and this disease is now known as a pan-ethnic disease. AGC2 (aspartate glutamate carrier 2) or citrin is a mitochondrial transporter which transports aspartate (Asp) from mitochondria to cytosol in exchange with glutamate (Glu) and H+. Asp is originally supplied from mitochondria to cytosol where it is necessary for synthesis of proteins, nucleotides, and urea. In cytosol, Asp can be synthesized from oxaloacetate and Glu by cytosolic Asp aminotransferase, but oxaloacetate formation is limited by the amount of NAD+. This means an increase in NADH causes suppression of Asp formation in the cytosol. Metabolism of carbohydrates and other substances which produce cytosolic NADH such as alcohol and glycerol suppress oxaloacetate formation. It is forced under citrin deficiency since citrin is a member of malate/Asp shuttle. In this review, we will describe history of identification of the SLC25A13 gene as the causative gene for adult-onset type II citrullinemia (CTLN2), a type of citrin deficiency, pathophysiology of citrin deficiency together with animal models and possible treatments for citrin deficiency newly developing.
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Bigot A, Tchan MC, Thoreau B, Blasco H, Maillot F. Liver involvement in urea cycle disorders: a review of the literature. J Inherit Metab Dis 2017; 40:757-769. [PMID: 28900784 DOI: 10.1007/s10545-017-0088-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 08/13/2017] [Accepted: 08/29/2017] [Indexed: 12/20/2022]
Abstract
Urea cycle disorders (UCDs) are inborn errors of metabolism of the nitrogen detoxification pathway and encompass six principal enzymatic deficiencies. The aging of UCD patients leads to a better knowledge of the long-term natural history of the condition and to the reporting of previously unnoticed manifestations. Despite historical evidence of liver involvement in UCDs, little attention has been paid to this organ until recently. Hence, we reviewed the available scientific evidence on acute and chronic liver dysfunction and liver carcinogenesis in UCDs and discuss their pathophysiology. Overall, liver involvement, such as acute liver failure or steatotic-like disease, which may evolve toward cirrhosis, has been reported in all six main UCDs. Excessive glycogen storage is also a prominent histologic feature, and hypoglycemia has been reported in citrin deficiency. Hepatocarcinomas seem frequent in some UCDs, such as in citrin deficiency, and can sometimes occur in non-cirrhotic patients. UCDs may differ in liver involvement according to the enzymatic deficiency. Ornithine transcarbamylase deficiency may be associated more with acute liver failure and argininosuccinic aciduria with chronic liver failure and cirrhosis. Direct toxicity of metabolites, downstream metabolic deficiencies, impaired tricarboxylic acid cycle, oxidative stress, mitochondrial dysfunction, energy deficit, and putative toxicity of therapies combine in various ways to cause the different liver diseases reported.
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Affiliation(s)
- Adrien Bigot
- CHRU de Tours, service médecine interne, Tours, France.
- CHRU de Tours, centre de référence des maladies héréditaires du métabolisme, Tours, France.
- Department of Genetic Medicine, Westmead Hospital, Sydney, Australia.
- Service de Médecine Interne, Hôpital Bretonneau, 2, boulevard Tonnelle, 37044, Tours, France.
| | - Michel C Tchan
- Department of Genetic Medicine, Westmead Hospital, Sydney, Australia
| | - Benjamin Thoreau
- CHRU de Tours, service médecine interne, Tours, France
- CHRU de Tours, centre de référence des maladies héréditaires du métabolisme, Tours, France
- Université François Rabelais, Tours, France
- UMR INSERM U 1069, Tours, France
| | - Hélène Blasco
- CHRU de Tours, centre de référence des maladies héréditaires du métabolisme, Tours, France
- Université François Rabelais, Tours, France
- CHRU de Tours, service de biochimie-biologie moléculaire, Tours, France
- UMR INSERM U930, 37000, Tours, France
| | - François Maillot
- CHRU de Tours, service médecine interne, Tours, France
- CHRU de Tours, centre de référence des maladies héréditaires du métabolisme, Tours, France
- Université François Rabelais, Tours, France
- UMR INSERM U 1069, Tours, France
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Lu CT, Shi QP, Li ZJ, Li J, Feng L. Blood glucose and insulin and correlation of SLC25A13 mutations with biochemical changes in NICCD patients. Exp Biol Med (Maywood) 2017; 242:1271-1278. [PMID: 28516797 DOI: 10.1177/1535370217710918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is a hereditary metabolic disease arising from biallelic mutations of SLC25A13. This study aimed to explore the characteristics of fasting blood glucose (FBG), fasting insulin (FINS) and C-peptide (C-P) levels in NICCD infants, analyze their SLC25A13 genetic mutations and further discuss the correlation between SLC25A13 genetic mutations and biochemical changes. Seventy-two cases of infants with cholestasis disease were gathered. Among them, 36 cases with NICCD diagnosis were case group. Meanwhile, 36 cases with unknown etiology but excluded NICCD were control group. FBG, FINS, C-P, ALT, AST, GGT, ALP, TG, HDL-C, LDL-C and Non-HDL-C were collected from all subjects, and DNA was extracted from venous blood for SLC25A13 mutations detection. The incidence of hypoglycemia was 3% in NICCD group. There were no significant statistical difference of FBG, FINS and C-P between NICCD and INC groups ( P > 0.05). ALT, LDL-C and Non-HDL-C levels in NICCD group were lower than the INC group, while SLC25A13 mutations were associated with the level of GGT ( P < 0.05). Ten different SLC25A13 genetic mutations were detected, among which, 851del4, IVS16ins3kb, IVS6+5 G > A and 1638ins23 mutations made up 82% of all mutations. The incidence of hypoglycemia may be higher in small gestational age infants with NICCD. Low LDL-C may be one of the characteristics of dyslipidemia in NICCD infants. There was a correlation between SLC25A13 gene mutations distribution and the GGT level, but the meaning of this finding remains to be further in-depth study. Impact statement This study aims to compare FBG, FINS, C-P, other biochemical and clinical manifestations between NICCD and non-NICCD infants, and discuss differential diagnosis of NICCD and INC beyond the genetic analysis. And investigate the correlation between SLC25A13 genetic mutations and biochemical changes. This work presented that incidence of hypoglycemia may be higher in small gestational age infants with NICCD. Low LDL-C may be one of the characteristics of dyslipidemia in NICCD infants. There was a correlation between SLC25A13 gene mutations distribution and the GGT level.
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Affiliation(s)
- Chun-Ting Lu
- 1 Science and Education Office, Jinan University, First Affiliated Hospital, Guangzhou 510630, China.,2 Department of Endocrinology and Metabolism, Jinan University, First Affiliated Hospital, Guangzhou 510630, China
| | - Qi-Ping Shi
- 2 Department of Endocrinology and Metabolism, Jinan University, First Affiliated Hospital, Guangzhou 510630, China
| | - Ze-Jian Li
- 3 Medical Centre of Stomatology, Jinan University, First Affiliated Hospital, Guangzhou 510630, China
| | - Jiong Li
- 4 Department of Anatomy, Medical School, Jinan University, Guangzhou 510630, China
| | - Lie Feng
- 2 Department of Endocrinology and Metabolism, Jinan University, First Affiliated Hospital, Guangzhou 510630, China
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Haschke-Becher E, Kainz A, Bachmann C. Reference values of amino acids and of common clinical chemistry in plasma of healthy infants aged 1 and 4 months. J Inherit Metab Dis 2016; 39:25-37. [PMID: 26227325 DOI: 10.1007/s10545-015-9870-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 05/07/2015] [Accepted: 05/26/2015] [Indexed: 12/30/2022]
Abstract
OBJECTIVE To compare plasma levels of amino acids and clinical chemistry parameters in healthy infants at 1 and 4 months of age and to establish corresponding reference limits. METHODS Data of three multicenter studies assessing the safety of new infant formulas were used. During these studies infants of both age-groups were either breast-fed or received formulas of low or high protein content. All samples were analyzed centrally in the same accredited laboratory. RESULTS Plasma was collected from 521 infants in total, 157 boys and 135 girls aged 1 month and 121 boys and 108 girls aged 4 months. At the age of 1 month, 62 infants had received exclusively breast milk, 198 exclusively formula, and 27 both; in the 4-months age group corresponding numbers were 49, 158 and 18, respectively; for 9 infants, diet was unknown. Concentrations of most amino acids and clinical chemistry parameters differed significantly between both ages. Regardless of age, most plasma amino acid levels were comparable or lower in breast-fed than in formula-fed infants whereas at 1 month of age most clinical chemistry parameters were higher. While in breast-fed infants the plasma urea concentration decreased over 4 months of age, it increased in formula-fed infants. There were significant differences between infants fed a low and high protein formula. At both ages, high protein formulas resulted in significantly higher threonine, 2-aminobutyrate, and urea concentrations. CONCLUSIONS For clinical use, age- and diet specific reference limits in infants are warranted.
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Affiliation(s)
| | - Alexander Kainz
- Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Claude Bachmann
- Laboratoire Central de Chimie Clinique, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rittergasse 11, CH-4103, Bottmingen, Switzerland.
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Liu G, Wei X, Chen R, Zhou H, Li X, Sun Y, Xie S, Zhu Q, Qu N, Yang G, Chu Y, Wu H, Lan Z, Wang J, Yang Y, Yi X. A novel mutation of the SLC25A13 gene in a Chinese patient with citrin deficiency detected by target next-generation sequencing. Gene 2014; 533:547-53. [DOI: 10.1016/j.gene.2013.10.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Revised: 10/06/2013] [Accepted: 10/11/2013] [Indexed: 01/29/2023]
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SLC25A13 gene analysis in citrin deficiency: sixteen novel mutations in East Asian patients, and the mutation distribution in a large pediatric cohort in China. PLoS One 2013; 8:e74544. [PMID: 24069319 PMCID: PMC3777997 DOI: 10.1371/journal.pone.0074544] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/02/2013] [Indexed: 12/19/2022] Open
Abstract
Background The human SLC25A13 gene encodes citrin, the liver-type mitochondrial aspartate/glutamate carrier isoform 2 (AGC2), and SLC25A13 mutations cause citrin deficiency (CD), a disease entity that encompasses different age-dependant clinical phenotypes such as Adult-onset Citrullinemia Type II (CTLN2) and Neonatal Intrahepatic Cholestasis caused by Citrin Deficiency (NICCD). The analyses of SLC25A13 gene and its protein/mRNA products remain reliable tools for the definitive diagnoses of CD patients, and so far, the SLC25A13 mutation spectrum in Chinese CD patients has not been well-characterized yet. Methods and Results By means of direct DNA sequencing, cDNA cloning and SNP analyses, 16 novel pathogenic mutations, including 9 missense, 4 nonsense, 1 splice-site, 1 deletion and 1 large transposal insertion IVS4ins6kb (GenBank accession number KF425758), were identified in CTLN2 or NICCD patients from China, Japan and Malaysia, respectively, making the SLC25A13 variations worldwide reach the total number of 81. A large NICCD cohort of 116 Chinese cases was also established, and the 4 high-frequency mutations contributed a much larger proportion of the mutated alleles in the patients from south China than in those from the north (χ2 = 14.93, P<0.01), with the latitude of 30°N as the geographic dividing line in mainland China. Conclusions This paper further enriched the SLC25A13 variation spectrum worldwide, and formed a substantial contribution to the in-depth understanding of the genotypic feature of Chinese CD patients.
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Chen R, Wang XH, Fu HY, Zhang SR, Abudouxikuer K, Saheki T, Wang JS. Different regional distribution of SLC25A13 mutations in Chinese patients with neonatal intrahepatic cholestasis. World J Gastroenterol 2013; 19:4545-4551. [PMID: 23901231 PMCID: PMC3725380 DOI: 10.3748/wjg.v19.i28.4545] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Revised: 04/24/2013] [Accepted: 06/04/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the differences in the mutation spectra of the SLC25A13 gene mutations from specific regions of China.
METHODS: Genetic analyses of SLC25A13 mutations were performed in 535 patients with neonatal intrahepatic cholestasis from our center over eight years. Unrelated infants with at least one mutant allele were enrolled to calculate the proportion of SLC25A13 mutations in different regions of China. The boundary between northern and southern China was drawn at the historical border of the Yangtze River.
RESULTS: A total of 63 unrelated patients (about 11% of cases with intrahepatic cholestasis) from 16 provinces or municipalities in China had mutations in the SLC25A13 gene, of these 16 (25%) were homozygotes, 28 (44%) were compound heterozygotes and 19 (30%) were heterozygotes. In addition to four well described common mutations (c.851_854del, c.1638_1660dup23, c.615+5G>A and c.1750+72_1751-4dup17insNM_138459.3:2667 also known as IVS16ins3kb), 13 other mutation types were identified, including three novel mutations: c.985_986insT, c.287T>C and c.1349A>G. According to the geographical division criteria, 60 mutant alleles were identified in patients from the southern areas of China, 43 alleles were identified in patients from the border, and 4 alleles were identified in patients from the northern areas of China. The proportion of four common mutations was higher in south region (56/60, 93%) than that in the border region (34/43, 79%, χ2 = 4.621, P = 0.032) and the northern region (2/4, 50%, χ2 = 8.288, P = 0.041).
CONCLUSION: The SLC25A13 mutation spectra among the three regions of China were different, providing a basis for the improvement of diagnostic strategies and interpretation of genetic diagnosis.
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Treepongkaruna S, Jitraruch S, Kodcharin P, Charoenpipop D, Suwannarat P, Pienvichit P, Kobayashi K, Wattanasirichaigoon D. Neonatal intrahepatic cholestasis caused by citrin deficiency: prevalence and SLC25A13 mutations among Thai infants. BMC Gastroenterol 2012; 12:141. [PMID: 23067347 PMCID: PMC3483206 DOI: 10.1186/1471-230x-12-141] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 10/08/2012] [Indexed: 01/13/2023] Open
Abstract
Background The most common causes of cholestatic jaundice are biliary atresia and idiopathic neonatal hepatitis (INH). Specific disorders underlying INH, such as various infectious and metabolic causes, including neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) especially, in East Asian populations are increasingly being identified. Since most NICCD infants recovered from liver disease by 1 year of age, they often are misdiagnosed with INH, leading to difficulty in determining the true prevalence of NICCD. Mutation(s) of human SLC25A13 gene encoding a mitochondrial aspartate/glutamate carrier isoform 2 (AGC2), can lead to AGC2 deficiency, resulting in NICCD and an adult-onset fatal disease namely citrullinemia type II (CTLN2). To study the prevalence of NICCD and SLC25A13 mutations in Thai infants, and to compare manifestations of NICCD and non-NICCD, infants with idiopathic cholestatic jaundice or INH were enrolled. Clinical and biochemical data were reviewed. Urine organic acid and plasma amino acids profiles were analyzed. PCR-sequencing of all 18 exons of SLC25A13 and gap PCR for the mutations IVS16ins3kb and Ex16+74_IVS17-32del516 were performed. mRNA were analyzed in selected cases with possible splicing error. Results Five out of 39 (12.8%) unrelated infants enrolled in the study were found to have NICCD, of which three had homozygous 851del4 (GTATdel) and two compound heterozygous 851del4/IVS16ins3kb and 851del4/1638ins23, respectively. Two missense mutations (p.M1? and p.R605Q) of unknown functional significance were identified. At the initial presentation, NICCD patients had higher levels of alkaline phosphatase (ALP) and alpha-fetoprotein (AFP) and lower level of alanine aminotransferase (ALT) than those in non-NICCD patients (p< 0.05). NICCD patients showed higher citrulline level and threonine/serine ratio than non-NICCD infants (p< 0.05). Fatty liver was found in 2 NICCD patients. Jaundice resolved in all NICCD and in 87.5% of non-NICCD infants at the median age of 9.5 and 4.0 months, respectively. Conclusion NICCD should be considered in infants with idiopathic cholestasis. The preliminary estimated prevalence of NICCD was calculated to be 1/48,228 with carrier rate of 1/110 among Thai infants. However, this number may be underestimated and required further analysis with mutation screening in larger control population to establish the true prevalence of NICCD and AGC2 deficiency.
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Affiliation(s)
- Suporn Treepongkaruna
- Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand
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Zhang ZH, Lin WX, Deng M, Zhao XJ, Song YZ. Molecular analysis of SLC25A13 gene in human peripheral blood lymphocytes: Marked transcript diversity, and the feasibility of cDNA cloning as a diagnostic tool for citrin deficiency. Gene 2012; 511:227-34. [PMID: 23022256 DOI: 10.1016/j.gene.2012.09.049] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/12/2012] [Accepted: 09/19/2012] [Indexed: 12/29/2022]
Abstract
Human SLC25A13 gene encodes citrin, the liver-type aspartate-glutamate carrier isoform 2, and SLC25A13 mutations lead to citrin deficiency (CD). The definitive diagnosis of CD relies on SLC25A13 analysis, but conventional DNA analysis could not identify all SLC25A13 mutations. We investigated transcriptional features of SLC25A13 gene in peripheral blood lymphocytes (PBLs) from CD patients and healthy volunteers. SLC25A13 mutations were explored by PCR/LA-PCR, PCR-RFLP and direct sequencing. SLC25A13 cDNA was amplified by RT-PCR, cloned and then sequenced. All diagnoses of the CD patients were confirmed, including a heterozygote of g.2T>C and an unknown mutation yielding an aberrant transcript r.16_212dup. Twenty-eight alternative splice variants (ASVs) were identified from normal SLC25A13 alleles. Among them, r.213_328del took account for 53.7%, the normal transcript r.=, 16.6%, and the remaining 26 novel ASVs, collectively 29.3%, of all cDNA clones. Moreover, similar ASVs, all reflecting corresponsive mutations, were detected from the mutated alleles. These results indicated that the normal SLC25A13 transcript could be cloned, and the abundance of the ASV r.213_328del predicted the existence of a constructively novel protein isoform for this gene in human PBLs. And, the 26 novel ASVs, along with the novel aberrant transcript r.16_212dup and the SNP g.2T>C, enriched the transcript/variation spectrum of SLC25A13 gene in human beings. The findings in this paper, for the first time, uncovered the marked transcript diversity of SLC25A13 gene in human PBLs, and suggested that cDNA cloning analysis of this gene in human PBLs might be a feasible tool for CD molecular diagnosis.
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Affiliation(s)
- Zhan-Hui Zhang
- Department of Pediatrics, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China
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Lin WX, Zhang ZH, Deng M, Cai XR, Song YZ. Multiple ovarian antral follicles in a preterm infant with neonatal intrahepatic cholestasis caused by citrin deficiency: A clinical, genetic and transcriptional analysis. Gene 2012; 505:269-75. [DOI: 10.1016/j.gene.2012.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 06/03/2012] [Accepted: 06/07/2012] [Indexed: 01/14/2023]
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Kikuchi A, Arai-Ichinoi N, Sakamoto O, Matsubara Y, Saheki T, Kobayashi K, Ohura T, Kure S. Simple and rapid genetic testing for citrin deficiency by screening 11 prevalent mutations in SLC25A13. Mol Genet Metab 2012; 105:553-8. [PMID: 22277121 DOI: 10.1016/j.ymgme.2011.12.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 12/29/2011] [Accepted: 12/30/2011] [Indexed: 12/29/2022]
Abstract
Citrin deficiency is an autosomal recessive disorder caused by mutations in the SLC25A13 gene and has two disease outcomes: adult-onset type II citrullinemia and neonatal intrahepatic cholestasis caused by citrin deficiency. The clinical appearance of these diseases is variable, ranging from almost no symptoms to coma, brain edema, and severe liver failure. Genetic testing for SLC25A13 mutations is essential for the diagnosis of citrin deficiency because chemical diagnoses are prohibitively difficult. Eleven SLC25A13 mutations account for 95% of the mutant alleles in Japanese patients with citrin deficiency. Therefore, a simple test for these mutations is desirable. We established a 1-hour, closed-tube assay for the 11 SLC25A13 mutations using real-time PCR. Each mutation site was amplified by PCR followed by a melting-curve analysis with adjacent hybridization probes (HybProbe, Roche). The 11 prevalent mutations were detected in seven PCR reactions. Six reactions were used to detect a single mutation each, and one reaction was used to detect five mutations that are clustered in a 21-bp region in exon 17. To test the reliability, we used this method to genotype blind DNA samples from 50 patients with citrin deficiency. Our results were in complete agreement those obtained using previously established methods. Furthermore, the mutations could be detected without difficulty using dried blood samples collected on filter paper. Therefore, this assay could be used for newborn screening and for facilitating the genetic diagnosis of citrin deficiency, especially in East Asian populations.
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Affiliation(s)
- Atsuo Kikuchi
- Department of Pediatrics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan.
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Fiermonte G, Parisi G, Martinelli D, De Leonardis F, Torre G, Pierri CL, Saccari A, Lasorsa FM, Vozza A, Palmieri F, Dionisi-Vici C. A new Caucasian case of neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD): a clinical, molecular, and functional study. Mol Genet Metab 2011; 104:501-6. [PMID: 21914561 DOI: 10.1016/j.ymgme.2011.08.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 08/19/2011] [Accepted: 08/19/2011] [Indexed: 12/29/2022]
Abstract
Citrin is the liver-specific isoform of the mitochondrial aspartate/glutamate carrier (AGC2). AGC2 deficiency is an autosomal recessive disorder with two age related phenotypes: neonatal intrahepatic cholestasis (NICCD, OMIM#605814) and adult-onset type II citrullinemia (CTLN2, OMIM#603471). NICCD arises within the first few weeks of life resulting in prolonged cholestasis and metabolic abnormalities including aminoacidemia and galactosuria. Usually symptoms disappear within the first year of life, thus making a diagnosis difficult after this time. In this study we report a new Caucasian case of NICCD, a seven week old Romanian boy with prolonged jaundice. Sequencing of the AGC2 gene showed a novel homozygous missense double-nucleotide (doublet) mutation, which produces the change of the glycine at position 437 into glutamate. Functional studies, carried out on the recombinant mutant protein, for the first time demonstrated, that NICCD is caused by a reduced transport activity of AGC2. The presence of AGC2 deficiency in other ethnic groups besides Asian population suggests further consideration for NICCD diagnosis of any neonate with an unexplained cholestasis; a prompt diagnosis is crucial to resolve the metabolic decompensation with an appropriate dietary treatment.
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Affiliation(s)
- Giuseppe Fiermonte
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy.
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Liver transplantation in an adult with citrullinaemia type 2. J Transplant 2011; 2011:176370. [PMID: 21647347 PMCID: PMC3103874 DOI: 10.1155/2011/176370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 03/18/2011] [Indexed: 11/17/2022] Open
Abstract
Citrullinaemia is a urea cycle defect that results from a deficiency of the enzyme arginosuccinate synthetase. Type 1 disease is diagnosed in childhood, whereas Type 2 disease is adult onset. We report the outcome of a patient with citrullinemia Type 2 who received a liver transplant at our center and the implications of this diagnosis in liver transplantation.
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Fu HY, Zhang SR, Wang XH, Saheki T, Kobayashi K, Wang JS. The mutation spectrum of the SLC25A13 gene in Chinese infants with intrahepatic cholestasis and aminoacidemia. J Gastroenterol 2011; 46:510-8. [PMID: 20927635 DOI: 10.1007/s00535-010-0329-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 09/10/2010] [Indexed: 02/04/2023]
Abstract
BACKGROUND SLC25A13 gene mutations cause citrin deficiency, which leads to neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). Information on the mutation spectrum of SLC25A13 in the Chinese population is limited. The aim of this study was to explore the mutation spectrum of the SLC25A13 gene in Chinese infants with intrahepatic cholestasis and various forms of aminoacidemia. METHODS Sequence analyses were performed on 39 infants with intrahepatic cholestasis and various forms of aminoacidemia. Novel mutations were subjected to homology and structural analyses. Western blots were performed when liver specimens available. RESULTS Genetic testing revealed the presence of SLC25A13 gene mutations (9 heterozygotes, 6 homozygotes and 13 compound heterozygotes) in 28 infants. Subsequent Western blot analysis revealed 22 cases of citrin deficiency, accounting for 56.4% of the 39 patients. Twelve types of mutations, including nine known mutations and three novel mutations, were found. Of the 49 mutated alleles, known ones include 851del4 (26 alleles, 53.1%), 1638ins23 (6 alleles, 12.2%), IVSl6ins3kb (3 alleles, 6.1%), IVS6+5G>A (2 alleles, 4.1%), E601K (2 alleles, 4.1%) and IVS11+1G>A, R184X, R360X and R585H (1 allele each, 2.0%). The three novel mutations were a splice site change (IVS6+1G>A), a deletion mutation (1092_1095delT) and a missense mutation (L85P), each in one allele. CONCLUSIONS The mutation spectrum of the SLC25A13 gene in a Chinese population of infants with intrahepatic cholestasis with various forms of aminoacidemia was found to be different from that of other population groups in East Asia. The SLC25A13 gene mutation is the most important cause of infantile intrahepatic cholestasis with various forms of aminoacidemia.
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Affiliation(s)
- Hai-Yan Fu
- The Center for Pediatric Liver Diseases, Children's Hospital of Fudan University, 399 Wanyuan Road, Minhang District, Shanghai 201102, People's Republic of China
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Mudd SH. Hypermethioninemias of genetic and non-genetic origin: A review. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2011; 157C:3-32. [PMID: 21308989 DOI: 10.1002/ajmg.c.30293] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This review covers briefly the major conditions, genetic and non-genetic, sometimes leading to abnormally elevated methionine, with emphasis on recent developments. A major aim is to assist in the differential diagnosis of hypermethioninemia. The genetic conditions are: (1) Homocystinuria due to cystathionine β-synthase (CBS) deficiency. At least 150 different mutations in the CBS gene have been identified since this deficiency was established in 1964. Hypermethioninemia is due chiefly to remethylation of the accumulated homocysteine. (2) Deficient activity of methionine adenosyltransferases I and III (MAT I/III), the isoenzymes the catalytic subunit of which are encoded by MAT1A. Methionine accumulates because its conversion to S-adenosylmethionine (AdoMet) is impaired. (3) Glycine N-methyltrasferase (GNMT) deficiency. Disruption of a quantitatively major pathway for AdoMet disposal leads to AdoMet accumulation with secondary down-regulation of methionine flux into AdoMet. (4) S-adenosylhomocysteine (AdoHcy) hydrolase (AHCY) deficiency. Not being catabolized normally, AdoHcy accumulates and inhibits many AdoMet-dependent methyltransferases, producing accumulation of AdoMet and, thereby, hypermethioninemia. (5) Citrin deficiency, found chiefly in Asian countries. Lack of this mitochondrial aspartate-glutamate transporter may produce (usually transient) hypermethioninemia, the immediate cause of which remains uncertain. (6) Fumarylacetoacetate hydrolase (FAH) deficiency (tyrosinemia type I) may lead to hypermethioninemia secondary either to liver damage and/or to accumulation of fumarylacetoacetate, an inhibitor of the high K(m) MAT. Additional possible genetic causes of hypermethioninemia accompanied by elevations of plasma AdoMet include mitochondrial disorders (the specificity and frequency of which remain to be elucidated). Non-genetic conditions include: (a) Liver disease, which may cause hypermethioninemia, mild, or severe. (b) Low-birth-weight and/or prematurity which may cause transient hypermethioninemia. (c) Ingestion of relatively large amounts of methionine which, even in full-term, normal-birth-weight babies may cause hypermethioninemia.
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Affiliation(s)
- S Harvey Mudd
- Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA.
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Yi P, Liu L, Mei H, Zeng F, Huang Z, Niu H. Establishment of reference range of plasma amino acids for younger Chinese children by reverse phase HPLC. J Pediatr Endocrinol Metab 2011; 24:733-8. [PMID: 22145465 DOI: 10.1515/jpem.2011.270] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Due to lack of country-specific norms in China, we established the reference range of plasma amino acids for younger Chinese children by reverse phase high-performance liquid chromatography (HPLC). METHODS Plasma proteins were precipitated with ethanol. L-Norvaline served as an internal standard. This HPLC method was based on automated precolumn derivatization using o-phthalaldehyde 3-mercaptopropionic acid for primary amino acids and 9-fluorenylmethyl chloroformate for secondary amino acids. Twenty-three amino acid derivatives were separated by a Zorbax Eclipse AAA column and detected fluorometrically. Plasma amino acids were measured in 108 healthy Chinese children (ages 0-5 years, 59 boys and 49 girls). RESULTS The assay was linear from 7.2 to 925.0 micromol/L for all amino acids. Recovery of amino acids added to plasma samples was 93%-107%. Within- and between-run reproducibility was 0.18%-6.27% and 2.94%-16.15%, respectively. Sex- and age-specific plasma amino acid reference range for younger Chinese children was established. In our study, the boys had significantly higher levels of glutamine, citrulline, and tryptophan than girls (p < 0.05), and the girls had a significantly higher level of alanine than boys (p < 0.05). Compared with the 0- to 1-year group, the 1- to 5-year group had significantly higher levels of citrulline, valine, phenylalanine, isoleucine, and sarcosine and lower levels of aspartate, glutamate, serine, threonine, alanine, methionine, and tryptophan (p < 0.05). CONCLUSIONS This study validates the HPLC method described here as a simple, rapid, and reliable assay. The reference range of plasma amino acids for younger Chinese children is different from that for Caucasian children and will facilitate our clinical diagnosis in the future.
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Affiliation(s)
- Peng Yi
- Department of Endocrinology and Metabolism, Guangzhou Women and Children's Medical Center, Guangzhou Medical College, Guangzhou, Guangdong, China
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High resolution melting analysis for the detection of SLC25A13 gene mutations in Taiwan. Clin Chim Acta 2010; 412:460-5. [PMID: 21134364 DOI: 10.1016/j.cca.2010.11.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 11/06/2010] [Accepted: 11/20/2010] [Indexed: 11/24/2022]
Abstract
BACKGROUND Citrin, encoded by SLC25A13 gene, is a mitochondrial solute transporter with a crucial role in urea, nucleotide and protein synthesis. SLC25A13 mutations cause two phenotypes, adult-onset type II citrullinemia and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). This study aimed to develop a high resolution melting (HRM) analysis for SLC25A13 mutation scanning and determine the carrier rate in Taiwan. METHODS DNAs from healthy subjects (n=479), and patients with hepatocellular carcinoma (HCC, n=100) and NICCD (n=5) were scanned in exons 6, 9, 11, 16, and 17 and parts of introns of SLC25A13 using HRM analysis. All mutations detected by HRM analysis were further confirmed by TaqMan method and/or direct sequencing. RESULTS In healthy subjects, seventeen carriers with mutants c.851_854del (n=10), c.1638_1660dup, c.615+5G>A (n=4), and two novel mutants, c.475C>T and c.1658G>A, were detected. The frequency of carriers was about 1/28. In patients with HCC, there were only 2 carriers with c.851_854del mutant. Patients with NICCD (n=5) diagnosed during 2007 and 2008, harbored compound heterozygous mutations c.851_854del/c.1177+1G>A, c.851_854del/c.1638_1660dup (n=2), c.851_854del/c.615+5G>A, and c.1638_1660dup/c.615+5G>A. CONCLUSIONS HRM analysis is a simple, rapid and robust method for detecting SLC25A13 mutations in clinical laboratories. SLC25A13 mutations may not be a major contributor to the pathogenesis of HCC in Taiwan.
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Chew HB, Ngu LH, Zabedah MY, Keng WT, Balasubramaniam S, Hanifah MJM, Kobayashi K. Neonatal intrahepatic cholestasis associated with citrin deficiency (NICCD): a case series of 11 Malaysian patients. J Inherit Metab Dis 2010; 33 Suppl 3:S489-95. [PMID: 21161389 DOI: 10.1007/s10545-010-9248-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Revised: 09/07/2010] [Accepted: 11/08/2010] [Indexed: 12/29/2022]
Abstract
Citrin deficiency, aetiologically linked to mutations of SLC25A13 gene, has two clinical phenotypes, namely adult-onset type II citrullinaemia (CTLN2) and neonatal/infantile intrahepatic cholestasis, caused by citrin deficiency (NICCD). Malaysian patients with NICCD, especially of Malay and East Malaysian indigenous descent, have never been reported in the literature. We present the clinical features, biochemical findings and results of molecular analysis in 11 Malaysian children with NICCD. In this case series, all patients manifested prolonged cholestatic jaundice and elevated citrulline levels. The other more variable features included failure to thrive, bleeding diathesis, hypoproteinaemia, abnormal liver enzymes, prolonged coagulation profile, hyperammonaemia, hypergalactosaemia, multiple aminoacidaemia, elevated α-feto protein and urinary orotic acid as well as liver biopsies showing hepatitis and steatosis. DNA analysis of SLC25A13 revealed combinations of 851del4(Ex9), IVS16ins3kb and 1638ins23. Most of our patients recovered completely by the age of 22 months. However, one patient had ongoing symptoms at the time of reporting and one had died of liver failure. Since a small percentage of children with NICCD will develop CTLN2 and the mechanisms leading to this is yet to be defined, ongoing health surveillance into adulthood is essential.
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Affiliation(s)
- Hui Bein Chew
- Genetic and Metabolic Unit, Department of Paediatrics, University Malaya Medical Centre, 50603 Kuala Lumpur, Malaysia.
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Hutchin T, Preece MA, Hendriksz C, Chakrapani A, McClelland V, Okumura F, Song YZ, Iijima M, Kobayashi K, Saheki T, McKiernan P, Baumann U. Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) as a cause of liver disease in infants in the UK. J Inherit Metab Dis 2009; 32 Suppl 1:S151-5. [PMID: 19517266 DOI: 10.1007/s10545-009-1116-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 04/07/2009] [Accepted: 04/14/2009] [Indexed: 12/22/2022]
Abstract
Citrin deficiency is a disorder with two phenotypes: neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and adult-onset type II citrullinaemia (CTLN2). NICCD presents in the first few weeks of life with prolonged cholestasis and metabolic abnormalities including aminoacidaemia (notably citrulline, tyrosine, threonine, arginine and methionine) and galactosuria. Symptoms resolve within the first year of life, thus making a diagnosis difficult after this time. Although patients subsequently remain generally healthy, some may develop more severe symptoms of CTLN2, characterized by neurological changes, one or more decades later. To date more than 400 cases have been reported, almost all from East Asia (mainly Japan). Here we describe the first two cases of NICCD in infants from the UK, one of caucasian origin and one of Pakistani origin. Both showed typical clinical and biochemical changes with a diagnosis confirmed by the presence of previously unreported mutations in the SLC25A13 gene. The presence of citrin deficiency in other ethnic groups means that NICCD needs to be considered in the diagnosis of any neonate with an unexplained cholestasis. We discuss both the difficulties in diagnosing these patients in populations where very few DNA mutations have been identified and the problems faced in the management of these patients. These findings also raise the possibility of adults with CTLN2 in whom a diagnosis has yet to be made.
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Affiliation(s)
- T Hutchin
- Department of Clinical Chemistry, Birmingham Children's Hospital, Whittall Street, Birmingham, B4 6NL, UK.
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Song YZ, Li BX, Chen FP, Liu SR, Sheng JS, Ushikai M, Zhang CH, Zhang T, Wang ZN, Kobayashi K, Saheki T, Zheng XY. Neonatal intrahepatic cholestasis caused by citrin deficiency: clinical and laboratory investigation of 13 subjects in mainland of China. Dig Liver Dis 2009; 41:683-9. [PMID: 19185551 DOI: 10.1016/j.dld.2008.11.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2008] [Revised: 11/13/2008] [Accepted: 11/13/2008] [Indexed: 12/11/2022]
Abstract
BACKGROUND Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is a novel inborn error of metabolism due to dysfunction of citrin protein, and much more information about this new disease is still needed for its clinical management. AIMS To investigate in detail the clinical and laboratory features of NICCD. PATIENTS 13 NICCD subjects in mainland of China diagnosed in our department since 2006. METHODS The anthropometric parameters of the patients at birth were compared with controls, representative biochemical changes and metabolome findings were investigated cross-sectionally, and mutations in the causative gene SLC25A13 were analyzed by protocols established previously. RESULTS The patients showed reduced birth weight, length and ponderal index. Main clinical manifestations consisted of jaundice, hepato/hepatosplenomegaly and steatohepatosis on ultrasonography. Biochemical analysis revealed intrahepatic cholestasis, delayed switch of AFP to albumin, and elevated triglyceride, total cholesterol and LDL-cholesterol together with reduced HDL-cholesterol. Metabolome findings included co-existence of markers for galactosemia and tyrosinemia in urine, and elevated Cit, Met, Thr, Tyr, Lys, Arg and Orn in blood. Mutations of 851-854del, IVS6+5G>A, 1638-1660dup, A541D, IVS16ins3kb, R319X and G333D were detected in the gene SLC25A13. CONCLUSIONS The diagnosis of NICCD cannot be established based just on the numerous but non-specific clinical manifestations and biochemical changes. The relatively specific metabolome features provide valuable tools for its screening and diagnosis, while SLC25A13 mutation analysis should be taken as one of the reliable tools for the definitive diagnosis. The body proportionality at birth, steatohepatosis on ultrasonography, delayed switch of AFP to albumin, dyslipidemia pattern, urinary metabolome features and the novel mutation G333D expanded the clinical spectrum of NICCD.
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Affiliation(s)
- Y-Z Song
- Department of Pediatrics, First Affiliated Hospital, Jinan University, Guangzhou 510630, China.
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Dimmock D, Maranda B, Dionisi-Vici C, Wang J, Kleppe S, Fiermonte G, Bai R, Hainline B, Hamosh A, O'Brien WE, Scaglia F, Wong LJ. Citrin deficiency, a perplexing global disorder. Mol Genet Metab 2009; 96:44-9. [PMID: 19036621 DOI: 10.1016/j.ymgme.2008.10.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2008] [Revised: 10/14/2008] [Accepted: 10/14/2008] [Indexed: 12/18/2022]
Abstract
Citrin deficiency, caused by mutations in SLC25A13, can present with neonatal intrahepatic cholestasis or with adult onset neuropsychiatric, hepatic and pancreatic disease. Until recently, it had been thought to be found mostly in individuals of East Asian ancestry. A key diagnostic feature has been the deficient argininosuccinate synthetase (ASS) activity (E.C. 6.3.4.5) in liver, with normal activity in skin fibroblasts. In this series we describe the clinical presentation of 10 patients referred to our laboratories for sequence analysis of the SCL25A13 gene, including several patients who presented with elevated citrulline on newborn screening. In addition to sequence analysis performed on all patients, ASS enzyme activity, citrulline incorporation and Western blot analysis for ASS and citrin were performed on skin fibroblasts if available. We have found 5 unreported mutations including two apparent founder mutations in three unrelated French-Canadian patients. In marked contrast to previous cases, these patients have a markedly reduced ASS activity in skin fibroblasts. The presence of citrin protein on Western blot in three of our cases reduces the sensitivity of a screening test based on protein immunoblotting. The finding of citrin mutations in patients of Arabic, Pakistani, French Canadian and Northern European origins supports the concept that citrin deficiency is a panethnic disease.
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Affiliation(s)
- David Dimmock
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, BCM225, Houston, TX 77030, USA
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Komatsu M, Yazaki M, Tanaka N, Sano K, Hashimoto E, Takei YI, Song YZ, Tanaka E, Kiyosawa K, Saheki T, Aoyama T, Kobayashi K. Citrin deficiency as a cause of chronic liver disorder mimicking non-alcoholic fatty liver disease. J Hepatol 2008; 49:810-20. [PMID: 18620775 DOI: 10.1016/j.jhep.2008.05.016] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/21/2008] [Accepted: 05/12/2008] [Indexed: 02/08/2023]
Abstract
BACKGROUND/AIMS Citrin deficiency caused by SLC25A13 gene mutations develops into adult-onset type II citrullinemia (CTLN2) and may be accompanied with hepatic steatosis and steatohepatitis. As its clinical features remain unclear, we aimed to explore the characteristics of fatty liver disease associated with citrin deficiency. METHODS The prevalence of hepatic steatosis in 19 CTLN2 patients was examined, and clinical features were compared with those of non-alcoholic fatty liver disease (NAFLD) patients without known SLC25A13 gene mutations. RESULTS Seventeen (89%) CTLN2 patients had steatosis, and 4 (21%) had been diagnosed as having NAFLD before appearance of neuropsychological symptoms. One patient had steatohepatitis. Citrin deficiency-associated fatty livers showed a considerably lower prevalence of accompanying obesity and metabolic syndrome, higher prevalence of history of pancreatitis, and higher serum levels of pancreatic secretory trypsin inhibitor (PSTI) than fatty livers without the mutations. Receiver operating characteristic curve analyses revealed that a body mass index < 20kg/m(2) and serum PSTI>29ng/mL were associated with citrin deficiency. CONCLUSIONS Patients presenting with non-alcoholic fatty liver unrelated to obesity and metabolic syndrome might have citrin deficiency, and serum PSTI may be a useful indicator for distinguishing this from conventional NAFLD.
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Affiliation(s)
- Michiharu Komatsu
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
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Tabata A, Sheng JS, Ushikai M, Song YZ, Gao HZ, Lu YB, Okumura F, Iijima M, Mutoh K, Kishida S, Saheki T, Kobayashi K. Identification of 13 novel mutations including a retrotransposal insertion in SLC25A13 gene and frequency of 30 mutations found in patients with citrin deficiency. J Hum Genet 2008; 53:534-545. [PMID: 18392553 DOI: 10.1007/s10038-008-0282-2] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Accepted: 03/09/2008] [Indexed: 12/20/2022]
Abstract
Deficiency of citrin, liver-type mitochondrial aspartate-glutamate carrier, is an autosomal recessive disorder caused by mutations of the SLC25A13 gene on chromosome 7q21.3 and has two phenotypes: neonatal intrahepatic cholestatic hepatitis (NICCD) and adult-onset type II citrullinemia (CTLN2). So far, we have described 19 SLC25A13 mutations. Here, we report 13 novel SLC25A13 mutations (one insertion, two deletion, three splice site, two nonsense, and five missense) in patients with citrin deficiency from Japan, Israel, UK, and Czech Republic. Only R360X was detected in both Japanese and Caucasian. IVS16ins3kb identified in a Japanese CTLN2 family seems to be a retrotransposal insertion, as the inserted sequence (2,667-nt) showed an antisense strand of processed complementary DNA (cDNA) from a gene on chromosome 6 (C6orf68), and the repetitive sequence (17-nt) derived from SLC25A13 was found at both ends of the insert. All together, 30 different mutations found in 334 Japanese, 47 Chinese, 11 Korean, four Vietnamese and seven non-East Asian families have been summarized. In Japan, IVS16ins3kb was relatively frequent in 22 families, in addition to known mutations IVS11 + 1G > A, 851del4, IVS13 + 1G > A, and S225X in 189, 173, 48 and 30 families, respectively; 851del4 and IVS16ins3kb were found in all East Asian patients tested, suggesting that these mutations may have occurred very early in some area of East Asia.
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Affiliation(s)
- Ayako Tabata
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Jian-Sheng Sheng
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Miharu Ushikai
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Yuan-Zong Song
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.,Department of Pediatrics, First Affiliated Hospital, Jinan University, Guangzhou, 510632, China
| | - Hong-Zhi Gao
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.,Department of Brain Surgery, The Second Clinical College of Fujian Medical University, Quanzhou, 362000, China
| | - Yao-Bang Lu
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.,Department of Biochemistry, Pharmacy College, Hunan University of Traditional Chinese Medicine, Changsha, 410007, China
| | - Fumihiko Okumura
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Mikio Iijima
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Kozo Mutoh
- Department of Pediatrics, Shimada Municipal Hospital, Shizuoka, 427-8502, Japan
| | - Shosei Kishida
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Takeyori Saheki
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.,Institute for Health Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
| | - Keiko Kobayashi
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.
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Feillet F, Merten M, Battaglia-Hsu SF, Rabier D, Kobayashi K, Straczek J, Brivet M, Favre E, Guéant JL. Evidence of cataplerosis in a patient with neonatal classical galactosemia presenting as citrin deficiency. J Hepatol 2008; 48:517-22. [PMID: 18207281 DOI: 10.1016/j.jhep.2007.11.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 11/07/2007] [Accepted: 11/10/2007] [Indexed: 12/04/2022]
Abstract
Classical galactosemia is an autosomal recessive disorder caused by a deficiency of the enzyme galactose-1-phosphate uridyltransferase. Undoubtedly, some of the short term complications are linked to the toxic effects of the accumulated abnormal metabolites (galactose-1-phosphate and galactitol). However, the physiopathology of neonatal liver failure remains unclear. We report the case of a 7-week-old girl who was first diagnosed with liver failure, hypoprotidaemia, ascites and generalized edemas. High citrulline (293 micromol/L), on initial plasma amino acid, suggested the diagnosis of citrin deficiency. As the citric acid cycle intermediates were non-detectable (oxoglutarate, succinate and citrate), a cataplerotic state was suspected. As a result, citrate (as an anaplerotic treatment) induced a clear improvement in her liver function. Four weeks later, this patient was switched to a galactose-free formula (as recommended in citrin deficiency with galactosemia) and her pathological status returned to normal. Citrin deficiency was later ruled out by molecular biology studies; then we reintroduced a galactose-containing formula which re-evoked rapidly vomiting, galactose aversion and hepatic cytolysis and the diagnosis of classical galactosemia was established. Our case clearly shows that cataplerosis could play a role in the pathophysiology of the neonatal liver disease observed in classical galactosemia.
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Affiliation(s)
- François Feillet
- Centre de Référence des Maladies Héréditaires du Métabolisme et Inserm U724, CHU et Faculté de Médecine de Nancy, France.
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28
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Abstract
Citrin is a liver-type mitochondrial aspartate-glutamate carrier encoded by the SLC25A13 gene, and its deficiency causes adult-onset type II citrullinemia and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). Here, the authors investigated clinical findings in Korean infants with NICCD and performed mutation analysis on the SLC25A13 gene. Of 47 patients with neonatal cholestasis, three infants had multiple aminoacidemia (involving citrulline, methionine, and arginine) and galactosemia, and thus were diagnosed as having NICCD. Two of these three showed failure to thrive. The laboratory findings showed hypoproteinemia and hyperammonemia, and liver biopsies revealed micro-macrovesicular fatty liver and cholestasis. The three patients each harbored compound heterozygous 1,638-1,660 dup/ S225X mutation, compound heterozygous 851del4/S225X mutation, and heterozygous 1,638-1,660 dup mutation, respectively. With nutritional manipulation, liver functions were normalized and catch-up growth was achieved. NICCD should be considered in the differential diagnosis of cholestatic jaundice in Korean infants.
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Affiliation(s)
- Jae Sung Ko
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Jung Han Song
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Sup Park
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jeong Kee Seo
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
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Ohura T, Kobayashi K, Tazawa Y, Abukawa D, Sakamoto O, Tsuchiya S, Saheki T. Clinical pictures of 75 patients with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). J Inherit Metab Dis 2007; 30:139-44. [PMID: 17323144 DOI: 10.1007/s10545-007-0506-1] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2006] [Revised: 12/23/2006] [Accepted: 01/08/2007] [Indexed: 12/13/2022]
Abstract
We clarified the clinical features of NICCD (neonatal intrahepatic cholestasis caused by citrin deficiency) by retrospective review of symptoms, management and long-term outcome of 75 patients. The data were generated from questionnaires to paediatricians in charge of the patients. Thirty of the patients were referred to hospitals before 1 month of age because of positive results in newborn screening (hypergalactosaemia, hypermethioninaemia, and hyperphenylalaninaemia). The other 45, the screen-negative patients, were referred to hospitals with suspected neonatal hepatitis or biliary atresia because of jaundice or discoloured stool. Most of the screen-negative patients presented before 4 months of age, and 11 had failure to thrive. Laboratory data showed elevated serum bile acid concentrations, hypoproteinaemia, low levels of vitamin K-dependent coagulation factors and hypergalactosaemia. Hypoglycaemia was detected in 18 patients. Serum amino acid analyses showed significant elevation of citrulline and methionine concentrations. Most of the patients were given a lactose-free and/or medium-chain triglyceride-enriched formula and fat-soluble vitamins. Symptoms resolved in all but two of the patients by 12 months of age. The two patients with unresolved symptoms suffered from progressive liver failure and underwent liver transplantation before their first birthday. Another patient developed citrullinaemia type II (CTLN2) at age 16 years. It is important to recognize that NICCD is not always a benign condition.
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Affiliation(s)
- T Ohura
- Depatment of Paediatrics, Tohoku University School of Medicine, Sendai, Japan.
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30
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Clinical pictures of 75 patients with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). J Inherit Metab Dis 2007. [PMID: 17323144 DOI: 10.1007/s10545-0070506-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We clarified the clinical features of NICCD (neonatal intrahepatic cholestasis caused by citrin deficiency) by retrospective review of symptoms, management and long-term outcome of 75 patients. The data were generated from questionnaires to paediatricians in charge of the patients. Thirty of the patients were referred to hospitals before 1 month of age because of positive results in newborn screening (hypergalactosaemia, hypermethioninaemia, and hyperphenylalaninaemia). The other 45, the screen-negative patients, were referred to hospitals with suspected neonatal hepatitis or biliary atresia because of jaundice or discoloured stool. Most of the screen-negative patients presented before 4 months of age, and 11 had failure to thrive. Laboratory data showed elevated serum bile acid concentrations, hypoproteinaemia, low levels of vitamin K-dependent coagulation factors and hypergalactosaemia. Hypoglycaemia was detected in 18 patients. Serum amino acid analyses showed significant elevation of citrulline and methionine concentrations. Most of the patients were given a lactose-free and/or medium-chain triglyceride-enriched formula and fat-soluble vitamins. Symptoms resolved in all but two of the patients by 12 months of age. The two patients with unresolved symptoms suffered from progressive liver failure and underwent liver transplantation before their first birthday. Another patient developed citrullinaemia type II (CTLN2) at age 16 years. It is important to recognize that NICCD is not always a benign condition.
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31
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Tokuhara D, Iijima M, Tamamori A, Ohura T, Takaya J, Maisawa S, Kobayashi K, Saheki T, Yamano T, Okano Y. Novel diagnostic approach to citrin deficiency: analysis of citrin protein in lymphocytes. Mol Genet Metab 2007; 90:30-6. [PMID: 17092749 DOI: 10.1016/j.ymgme.2006.09.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 09/28/2006] [Accepted: 09/28/2006] [Indexed: 01/07/2023]
Abstract
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.
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Affiliation(s)
- Daisuke Tokuhara
- Department of Pediatrics, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abenoku, Osaka 545-8585, Japan
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Yeh JN, Jeng YM, Chen HL, Ni YH, Hwu WL, Chang MH. Hepatic steatosis and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) in Taiwanese infants. J Pediatr 2006; 148:642-6. [PMID: 16737877 DOI: 10.1016/j.jpeds.2005.12.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 09/09/2005] [Accepted: 12/06/2005] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To explore the prevalence of hepatic steatosis and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) in Taiwanese infants with idiopathic intrahepatic cholestasis. STUDY DESIGN The liver specimens from 69 infants with idiopathic intrahepatic cholestasis were reviewed (1993-2004); 11 of them (14.7%) had hepatic steatosis. Six patients with hepatic steatosis participated in the genetic study for the SLC25A13 gene under parental consent. RESULTS Infants with cholestasis and hepatic steatosis had lower aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels than those with cholestasis alone. Three of the six infants in the genetic study had homozygous 851del4 mutation; for the others, homozygous 1638ins23 mutation, compound heterozygous 851del4/IVS6+5G-->A mutation, and heterozygous IVS6+5G-->A mutation were found for each one. Eleven of the total 12 alleles (91.7%) were demonstrated to have SLC25A13 gene mutations. CONCLUSIONS Metabolic and genetic studies for NICCD should be performed in Asian infants with idiopathic intrahepatic cholestasis and hepatic steatosis. The 851del4 mutation on the SLC25A13 gene accounts for the major genotype expression of patients with NICCD in Taiwan.
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Affiliation(s)
- Jiun-Nan Yeh
- Department of Pediatrics, Department of Pathology, National Taiwan University Hospital, Taipei, Taiwan
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33
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Takaya J, Kobayashi K, Ohashi A, Ushikai M, Tabata A, Fujimoto S, Yamato F, Saheki T, Kobayashi Y. Variant clinical courses of 2 patients with neonatal intrahepatic cholestasis who have a novel mutation of SLC25A13. Metabolism 2005; 54:1615-9. [PMID: 16311094 DOI: 10.1016/j.metabol.2005.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2005] [Accepted: 06/14/2005] [Indexed: 12/16/2022]
Abstract
Deficiency of citrin due to mutations of the SLC25A13 gene causes not only adult-onset type II citrullinemia, but also neonatal intrahepatic cholestasis. Neonatal intrahepatic cholestasis is a self-limiting condition and spontaneously disappears by 12 months of age without special treatment. The natural history of patients with SLC25A13 mutations is not clear. Two patients with infantile hepatic dysfunction were found to have a novel mutation of the SLC25A13 gene. DNA analyses of SLC25A13 disclosed that the first patient was a compound heterozygote for the Ex16+74_IVS17-32del516 (del516-Ex16/IVS17) and IVS11+1G-->A mutations and the second one a homozygote for the del516-Ex16/IVS17 mutation. It is predicted that the 516-base pair deletion mutation leads to a frameshift from codons 556 to 564, a premature termination at codon 565, and a truncated form of the citrin protein (normal, 675 amino acids). The first patient had disseminated intravascular coagulation associated with hepatic dysfunction in the neonatal period. The other patient had persistent cholestatic jaundice and underwent an operation to rule out bile duct atresia. Without specific treatment, both patients had a favorable clinical course. In conclusion, citrin deficiency resulting from the mutation of SLC25A13 presented variant clinical courses, followed by hypercitrullinemia and intrahepatic cholestasis in infancy. The conditions in the patients were self-limiting and spontaneously disappeared.
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Affiliation(s)
- Junji Takaya
- Department of Pediatrics, Kansai Medical University, Moriguchi, Osaka 570-8506, Japan.
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Lu YB, Kobayashi K, Ushikai M, Tabata A, Iijima M, Li MX, Lei L, Kawabe K, Taura S, Yang Y, Liu TT, Chiang SH, Hsiao KJ, Lau YL, Tsui LC, Lee DH, Saheki T. Frequency and distribution in East Asia of 12 mutations identified in the SLC25A13 gene of Japanese patients with citrin deficiency. J Hum Genet 2005; 50:338-346. [PMID: 16059747 DOI: 10.1007/s10038-005-0262-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Accepted: 05/26/2005] [Indexed: 02/07/2023]
Abstract
Deficiency of citrin, a liver-type mitochondrial aspartate-glutamate carrier (AGC), encoded by the SLC25A13 gene on chromosome 7q21.3, causes autosomal recessive disorders: adult-onset type II citrullinemia (CTLN2) and neonatal hepatitis associated with intrahepatic cholestasis (NICCD). So far, we have described 12 SLC25A13 mutations: 11 were from Japan and one from Israel. Three mutations found in Chinese and Vietnamese patients were the same as those in Japanese patients. In the present study, we identified a novel mutation IVS6+1G>C in a Japanese CTLN2 patient and widely screened 12 SLC25A13 mutations found in Japanese patients in control individuals from East Asia to confirm our preliminary results that the carrier frequency was high in Asian populations. Mutations 851-854del and 1638-1660dup were found in all Asian countries tested, and 851-854del associated with 290-haplotype in microsatellite marker D7S1812 was especially frequent. Other mutations frequently detected were IVS11+1G>A in Japanese and Korean, S225X in Japanese, and IVS6+5G>A in Chinese populations. We found a remarkable difference in carrier rates in China (including Taiwan) between north (1/940) and south (1/48) of the Yangtze River. We detected many carriers in Chinese (64/4169 = 1/65), Japanese (20/1372 = 1/69) and Korean (22/2455 = 1/112) populations, suggesting that over 80,000 East Asians are homozygotes with two mutated SLC25A13 alleles.
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Affiliation(s)
- Yao Bang Lu
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Keiko Kobayashi
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.
| | - Miharu Ushikai
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Ayako Tabata
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Mikio Iijima
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Meng Xian Li
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Lei Lei
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Kotaro Kawabe
- Division of Gene Research, Research Centre for Life Science Resources, Kagoshima University, Kagoshima, Japan
| | - Satoru Taura
- Division of Gene Research, Research Centre for Life Science Resources, Kagoshima University, Kagoshima, Japan
| | - Yanling Yang
- Department of Pediatrics, The First Hospital of Peking University, Beijing, China
| | - Tze-Tze Liu
- Genome Research Center, National Yang-Ming University, Taipei, Taiwan, ROC
| | | | | | - Yu-Lung Lau
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Lap-Chee Tsui
- Vice Chancellor's Office, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Dong Hwan Lee
- Department of Pediatrics, Soonchunhyang University Hospital, Seoul, Korea
| | - Takeyori Saheki
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
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35
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Tazawa Y, Kobayashi K, Abukawa D, Nagata I, Maisawa S, Sumazaki R, Iizuka T, Hosoda Y, Okamoto M, Murakami J, Kaji S, Tabata A, Lu YB, Sakamoto O, Matsui A, Kanzaki S, Takada G, Saheki T, Iinuma K, Ohura T. Clinical heterogeneity of neonatal intrahepatic cholestasis caused by citrin deficiency: case reports from 16 patients. Mol Genet Metab 2004; 83:213-9. [PMID: 15542392 DOI: 10.1016/j.ymgme.2004.06.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2004] [Revised: 06/26/2004] [Accepted: 06/28/2004] [Indexed: 02/06/2023]
Abstract
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.
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Affiliation(s)
- Yusaku Tazawa
- Department of Pediatrics, Miyagi South Medical Center Hospital, Oogawara, Japan
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36
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Saheki T, Kobayashi K, Iijima M, Horiuchi M, Begum L, Jalil MA, Li MX, Lu YB, Ushikai M, Tabata A, Moriyama M, Hsiao KJ, Yang Y. 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. Mol Genet Metab 2004; 81 Suppl 1:S20-6. [PMID: 15050970 DOI: 10.1016/j.ymgme.2004.01.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Revised: 10/04/2003] [Accepted: 10/21/2003] [Indexed: 10/26/2022]
Abstract
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.
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Affiliation(s)
- Takeyori Saheki
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
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37
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Abstract
Conjugated hyperbilirubinaemia in an infant indicates neonatal liver disease. This neonatal hepatitis syndrome has numerous possible causes, classified as infective, anatomic/structural, metabolic, genetic, neoplastic, vascular, toxic, immune and idiopathic. Any infant who is jaundiced at 2-4 weeks old needs to have the serum conjugated bilirubin measured, even if he/she looks otherwise well. If conjugated hyperbilirubinaemia is present, a methodical and comprehensive diagnostic investigation should be performed. Early diagnosis is critical for the best outcome. In particular, palliative surgery for extrahepatic biliary atresia has the best chance of success if performed before the infant is 8 weeks old. Definitive treatments available for many causes of neonatal hepatitis syndrome should be started as soon as possible. Alternatively, liver transplantation may be life saving. Supportive care, especially with attention to nutritional needs, is important for all infants with neonatal hepatitis syndrome.
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Affiliation(s)
- Eve A Roberts
- Division of Gastroenterology and Nutrition, Room 8267, Black Wing, The Hospital for Sick Children, Toronto, Ontario, Canada.
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38
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Sinasac DS, Moriyama M, Jalil MA, Begum L, Li MX, Iijima M, Horiuchi M, Robinson BH, Kobayashi K, Saheki T, Tsui LC. Slc25a13-knockout mice harbor metabolic deficits but fail to display hallmarks of adult-onset type II citrullinemia. Mol Cell Biol 2004; 24:527-36. [PMID: 14701727 PMCID: PMC343808 DOI: 10.1128/mcb.24.2.527-536.2004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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.
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Affiliation(s)
- David S Sinasac
- Genetics & Genomic Biology, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
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