OBJECTIVE: To explore the characteristics of SLC25A13 gene variants in 16 infants with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). METHODS: The infants were subjected to high-throughput DNA sequencing for coding exons and flanking regions of the target genes. Suspected variants were verified by Sanger sequencing and bioinformatic analysis. RESULTS: Among the 16 NICCD cases, 15 were found to harbor pathogenic variants. Among these, IVS14-9A>G, c.1640G>A, c.762T>A, c.736delG, c.1098Tdel and c.851G>A were previously unreported. CONCLUSION Six novel SLC25A13 variants were found by high-throughput sequencing, which has enriched the spectrum of SLC25A13 gene variants and provided a basis for genetic counseling and prenatal diagnosis.
Calcium-Binding Proteins/genetics* ; Cholestasis, Intrahepatic/genetics* ; Citrullinemia/genetics* ; Humans ; Infant ; Infant, Newborn ; Mitochondrial Membrane Transport Proteins/genetics* ; Mutation ; Organic Anion Transporters/genetics* ; Protein Deficiency

Calcium-Binding Proteins ; deficiency ; Humans ; Infant ; Male ; Organic Anion Transporters ; deficiency ; Phenylketonurias ; complications ; diagnosis ; etiology

OBJECTIVETo analyze the clinical features and SLC25A13 gene mutations of a child with citrin deficiency complicated with purpura, convulsive seizures and methioninemia.

METHODSThe patient was subjected to physical examination and routine laboratory tests. Blood amino acids and acylcarnitines, and urine organic acids and galactose were analyzed respectively with tandem mass spectrometry and gas chromatographic mass spectrometry. SLC25A13 gene mutation screening was conducted by high resolution melt (HRM) analysis.

RESULTSThe petechiae on the patient's face and platelet count (27×10(9)/L, reference range 100×10(9)/L-300×10(9)/L) supported the diagnosis of immunologic thrombocytopenic purpura (ITP). Laboratory tests found that the patient have abnormal coagulation, cardiac enzyme, liver function and liver enzymes dysfunction. Tandem mass spectrometry also found methionine to be increased (286 μmol/L, reference ranges 8-35 μmol/L). The patient did not manifest any galactosemia, citrullinemia and tyrosinemia. Analysis of SLC25A13 gene mutation found that the patient has carried IVS16ins3kb, in addition with abnormal HRM result for exon 6. Direct sequencing of exon 6 revealed a novel mutation c.495delA. The same mutation was not detected in 100 unrelated healthy controls. Further analysis of her family has confirmed that the c.495delA mutation has derived from her farther, and that the IVS16ins3kb was derived from her mother.

CONCLUSIONThe clinical features and metabolic spectrum of citrin deficiency can be variable. The poor prognosis and severity of clinical symptoms of the patient may be attributed to the novel c.495delA mutation.

Amino Acid Metabolism, Inborn Errors ; genetics ; pathology ; Calcium-Binding Proteins ; deficiency ; genetics ; DNA Mutational Analysis ; methods ; Female ; Glycine N-Methyltransferase ; deficiency ; genetics ; Humans ; Infant ; Mitochondrial Membrane Transport Proteins ; genetics ; Organic Anion Transporters ; deficiency ; genetics ; Pedigree ; Purpura ; genetics ; pathology ; Seizures ; genetics ; pathology

Biliary Atresia ; diagnosis ; etiology ; therapy ; Bilirubin ; blood ; Biomarkers ; blood ; Calcium-Binding Proteins ; deficiency ; Cholangiopancreatography, Magnetic Resonance ; Cholestasis, Intrahepatic ; diagnosis ; etiology ; therapy ; Citrullinemia ; diagnosis ; etiology ; therapy ; DNA Mutational Analysis ; Humans ; Infant ; Jaundice ; diagnosis ; etiology ; therapy ; Liver Function Tests ; Male ; Mitochondrial Membrane Transport Proteins ; genetics ; Mutation ; Organic Anion Transporters ; deficiency

OBJECTIVETo investigate the diagnostic value of histopathological changes in the liver of patients with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD).

METHODSLiver specimens from 10 cases of NICCD were evaluated by hematoxylin-eosin stain, histochemistry and immunohistochemistry (EnVision method). SLC25A13 mutation analysis was performed to correlate with histopathology.

RESULTSMost specimens showed varying degrees of fat deposition in hepatocytes, necrotic inflammation, cholestasis and fibrosis (so-called tetralogy). The combination of the above four histological changes was highly characteristic for NICCD. With the progression of the disease, hepatic fibrosis deteriorated and ultimately led to cirrhosis.

CONCLUSIONSNICCD should be suspected in the presence of cholestasis during infancy. A liver biopsy must be performed to rule out other liver diseases. The tetralogy of the hepatic histopathological changes has a highly diagnostic value for NICCD, which is also practical for accurately assessing the degree of inflammation and fibrosis, and similarly the progression of hepatic cirrhosis.

Biopsy ; Calcium-Binding Proteins ; deficiency ; genetics ; metabolism ; Cholestasis, Intrahepatic ; etiology ; genetics ; pathology ; Disease Progression ; Female ; Hepatocytes ; pathology ; Humans ; Infant ; Liver ; pathology ; Liver Cirrhosis ; pathology ; Male ; Mitochondrial Membrane Transport Proteins ; genetics ; Mutation ; Organic Anion Transporters ; deficiency ; genetics ; metabolism

OBJECTIVEThis research intends to amplify the entire coding region sequences of SLC25A13 mRNA which encodes citrin, and to investigate sequence features of the transcripts for this gene in cultured human amniocytes. This study will provide laboratory evidence for prenatal diagnosis of neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) at mRNA level.

METHODSOne amniocyte sample was collected from a pregnant woman who underwent prenatal diagnosis of citrin deficiency and whose fetus has proven a carrier of 851del4 mutation by genomic DNA analysis. Another amniocyte sample, as a control, was from a fetus without family history of citrin deficiency. Total RNA was extracted from cultured amniocytes, cDNA was synthesized, and then nested-PCR was performed to amplify the entire coding region sequences of SLC25A13. The PCR products were cloned and analyzed by sequencing.

RESULTSThe entire coding region of SLC25A13 gene was successful amplified from two cultured human amniocytes. The splice variant of SLC25A13, SLCA (normal mRNA), was identified in the two samples. SLCB (CAG insertion between exon 9-10) was identified in the control. SLCC (exon 5-11 skipping), but not transcriptional product from the allele with 851del4 mutation, was identified in the 851del4 mutation carrier.

CONCLUSIONSThis study demonstrated that the entire coding region of SLC25A13 cDNA can be successfully amplified from two cultured human amniocytes, and revealed exon 5-11 skipping as a novel SLC25A13 transcript. Normal mRNA predominated in the transcripts in normal control and 851del4 mutation carrier, suggesting that the two fetuses were not at risk for NICCD. These SLC25A13 transcription features provided laboratory evidence for prenatal diagnosis of NICCD.

Amniotic Fluid ; cytology ; metabolism ; Calcium-Binding Proteins ; deficiency ; Cholestasis, Intrahepatic ; diagnosis ; Cloning, Molecular ; Female ; Humans ; Mitochondrial Membrane Transport Proteins ; genetics ; Organic Anion Transporters ; deficiency ; Polymerase Chain Reaction ; Pregnancy ; Prenatal Diagnosis ; methods ; RNA, Messenger ; analysis ; Sequence Analysis, DNA ; Transcription, Genetic

OBJECTIVETo assess the feasibility of high-resolution melting (HRM) analysis for screening patients with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD).

METHODSBased on previous studies on SLC25A13 gene in Chinese patients with NICCD, four hotspot mutations (851del4, 1638ins23, IVS6+5G>A and IVS16ins3kb) were selected. Results of the HRM analysis was validated using 50 negative controls and 20 patients with NICCD whose genotypes were confirmed previously by direct sequencing. With the established protocol, 171 suspected patients were enrolled. Samples with abnormal melting curves were further validated by DNA sequencing.

RESULTSHRM analysis can accurately determine the genotypes of all negative controls and patients. The sensitivity and specificity of the technique reached 100% (70/70). The melting curves of samples with the same genotype were highly reproducible. In 171 suspected patients, seven NICCD patients were detected by HRM. Identified mutations have included one case of 851del4 homozygote, one case of IVS6+5G>A heterozygote, 3 cases of 851del4 heterozygotes, one case of [IVS6+5G>A]+[ 851del4] and one case of [1638ins23+IVS16ins3kb]+[1638ins23]. All mutations were subsequently confirmed by DNA sequencing.

CONCLUSIONHRM analysis is a convenient, high-throughput and rapid technique for the screening of NICCD patients.

Anion Transport Proteins ; genetics ; Base Sequence ; Calcium-Binding Proteins ; deficiency ; China ; Citrullinemia ; diagnosis ; genetics ; metabolism ; DNA ; chemistry ; genetics ; Genetic Predisposition to Disease ; Genotype ; Humans ; Mitochondrial Proteins ; genetics ; Molecular Sequence Data ; Mutation ; Nucleic Acid Denaturation ; Organic Anion Transporters ; deficiency ; Sensitivity and Specificity

OBJECTIVETo ascertain whether the carrier rate is high in Quanzhou which is next to Taiwan in South of the Yangtze River.

METHODSPopulation analysis of three SLC25A13 mutations, i.e. 851del4, 1638-1660 dup, and IVS6+ 5G to A was carried out in 450 healthy individuals. DNA diagnostic method of 851del4 was improved by using PCR-restriction fragment length polymorphism( PCR-RFLP) with restriction enzyme HpyCH4 IV, and the results were confirmed by GeneScan method.

RESULTSSix carriers with 851del4, 3 with 1638-1660 dup and 3 with IVS6+ 5G to A was found.

CONCLUSIONThe high carrier rate (0.027, 12/450) obtained from testing of only three mutations indicated that there must be a certain number of patients with citrin deficiency in Quanzhou, even in Fujian. Therefore, it is important for physicians in Quanzhou, Fujian province to learn about citrin deficiency, and to diagnose and treat the patients correctly.

Asian Continental Ancestry Group ; genetics ; Base Sequence ; Calcium-Binding Proteins ; deficiency ; China ; DNA Mutational Analysis ; methods ; Female ; Humans ; Male ; Mitochondrial Membrane Transport Proteins ; genetics ; Organic Anion Transporters ; deficiency ; Polymorphism, Single Nucleotide ; genetics ; Sequence Deletion ; genetics

OBJECTIVETo investigate the clinical and laboratory features of neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and to characterize the molecular basis and prognosis of this disease.

METHODSTwenty-six patients with NICCD were collected because of idiopathic intrahepatic cholestasis and jaundice. The diagnosis was made by routine laboratory data collection, tandem mass spectrometry (MS-MS) and gas chromatography mass spectrometry (GC-MS) analyses. SLC25A13 gene mutation was analyzed by using polymerase chain reaction (PCR), direct DNA sequencing and restriction fragment length polymorphism analyses. The patients were followed up for nearly 2 years.

RESULTSThe NICCD patients showed low birth weight and the average onset of jaundice was 29 days. Laboratory data showed liver dysfunction, hyperbilirubinemia, hypoproteinemia, high levels of alpha-fetoprotein, prolonged prothrombin time, hypoglycemia and hyperammonemia. MS-MS analysis of the blood samples revealed specific elevation of citrulline, methionine, threonine, tyrosine and elevation of free carnitine, short-chain and long-chain acylcarnitines. GC-MS analysis of the urine samples showed elevated 4-hydroxyl phenyllactic acid and 4-hydroxyl phenylpyruvic acid. Twelve different mutations were identified, including 4 novel mutations, i.e., G386V, R467X, K453R and 1192-1193delT. Forty-four mutated alleles were identified in the 52 alleles (84.6% ). Among them, 851del4, 1638ins23 and IVS6+5G>A mutations were the most frequent mutations, accounting for 40.9%, 20.5% and 11.4% of the total alleles examined respectively. Five of the 26 patients have not been recovered, including 4 died and 1 accepted liver transplantation. No obvious relationship was found between the genotype and phenotype in NICCD.

CONCLUSIONThe 851del4, 1638ins23 and IVS6+5G>A mutations are the hot-spot mutations in Chinese NICCD patients. Some NICCD patients have poor prognosis.

Base Sequence ; Calcium-Binding Proteins ; deficiency ; Case-Control Studies ; Child, Preschool ; Cholestasis, Intrahepatic ; diagnosis ; etiology ; genetics ; therapy ; DNA Mutational Analysis ; Disease Progression ; Follow-Up Studies ; Genotype ; Humans ; Infant ; Infant, Newborn ; Male ; Mitochondrial Membrane Transport Proteins ; genetics ; Mutation ; Organic Anion Transporters ; deficiency ; Prognosis

Two clinical phenotypes for citrin deficiency (CD) have been reported. One is adult-onset citrullinemia type II (CTLN2) and another is neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). A child with CD and who had failure to thrive (FTT) and dyslipidemia as main clinical manifestations is reported here. Both the weight-and length-for-age at 18 months dropped below the 3rd percentile in the corresponding WHO anthropometry percentile charts, while blood biochemical analysis revealed dramatically increased triglyceride and total cholesterol, together with reduced HDL-cholesterol. Inquiries revealed his aversion to rice and fondness for fish since the age of one year, a peculiar habit which could not be corrected. Since the age of two years, the peculiar diet became more obvious, and slightly increased citrulline and threonine levels were detected on blood amino acid analysis. At the age of two years and five months he was suspected to have CD. Since then, he has been fed in accordance with his own food preferences, and FTT improved gradually, with weight-for-age, in particular, recovering beyond the 3rd percentile at three years of age, and dyslipidemia was also ameliorated gradually. SLC25A13 gene analysis revealed a homozygote of 851del4, and CD was thus confirmed. Diet survey at four years and seven months revealed a fondness for high-protein and low-carbohydrate foods, such as seafood, meat, eggs and milk. This child presented with FTT and dyslipidemia as main clinical manifestations and this was a novel CD phenotype different from NICCD and CTLN2.
Body Weight ; Calcium-Binding Proteins ; deficiency ; Cholestasis, Intrahepatic ; etiology ; Citrulline ; blood ; Dyslipidemias ; etiology ; Failure to Thrive ; etiology ; Humans ; Infant ; Lipids ; blood ; Male ; Mitochondrial Membrane Transport Proteins ; genetics ; Mutation ; Organic Anion Transporters ; deficiency ; Phenotype