OBJECTIVETo explore the major etiological features of cholestatic liver disease (CLD) in children, and to investigate the molecular epidemiological distribution of SLC25A13 mutations in CLD.

METHODA clinical cross-sectional investigation was performed on 63 CLD cases diagnosed from Oct. 2003 to Mar. 2009 in our department, including 36 males and 27 females. Their clinical data were collected, and etiology and prognosis were analyzed and summarized. Thirteen to 17 mutations in SLC25A13 gene were screened by means of procedures established previously by our group. Several SLC25AJ3 mutations were detected by direct sequencing of DNA fragments amplified by genomic DNA-PCR.

RESULTNo specific etiologies were identified in 24 of the 63 cases. Among the 39 cases with identified etiologies, inherited metabolic diseases were on top of the list, including 6 kinds and 27 cases in total, i.e., neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD, 21 cases), transient galactosemia, tyrosinemia type I, galactose kinase deficiency, ornithine carbamoyl transferase deficiency and glycogen storage disease type I, followed by acquired causes (7 cases in total), such as total parenteral nutrition associated cholestasis (TPNAC), congenital syphilis and CMV hepatitis; and then biliary tract malformation (5 cases in total), including biliary atresia, Caroli's disease and gallbladder polyp, were the third. Ten of the 55 patients on follow-up have passed away, while the remaining 45 cases were improved or recovered clinically. SLC25A13 gene analysis were performed in 44 CLD subjects and 21 of them from 20 families (with 40 SLC25A13 alleles in total) were found to have mutations, and the seven mutations detected were 851-854del (23/40), IVS6 + 5G > A (6/40), IVS16ins3kb (3/40), 1638-1660dup (2/30), A541D (1/30), R319X (1/30) and G333D (1/30), respectively, and there were other 3 mutations (3/40) still needing identification in the remaining 3 alleles.

CONCLUSIONThe etiologies for CLD in some cases can not be identified. However, inherited metabolic diseases, including NICCD in particular, constitute common causative factors for CLD. Most of the CLD conditions can be improved, even recovered clinically, although some cases presented with poor prognosis. Seven mutations in SLC25A13 gene were detected, among which, 851-854del, IVS6 + 5G > A, IVS16ins3kb and 1638-1660dup were the leading four mutations, respectively.

Child ; Child, Preschool ; China ; epidemiology ; Cholestasis, Intrahepatic ; diagnosis ; epidemiology ; genetics ; Cross-Sectional Studies ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mitochondrial Membrane Transport Proteins ; deficiency ; genetics ; Molecular Epidemiology ; Mutation ; Prognosis

OBJECTIVENeonatal intrahepatic cholestasis caused by citrin deficiency (NICCD, MIM#605814) is an inherited metabolic disease resulting from mutations of the gene SLC25A13, which encodes citrin, a liver-type mitochondrial aspartate-glutamate carrier. Mutation analysis is necessary for definitive diagnosis of NICCD patients. So far (March, 2007), 36 kinds of mutation, including 7 nonsense, 10 missense, 11 abnormal splicing, 4 insertion and 4 deletion, have been identified by Kobayashi's group, who cloned the gene in Kagoshima, Japan. To date, most of the NICCD patients reported in the world are Japanese. This study aimed to explore the gene diagnosis procedure of two known SLC25A13 mutations in a pedigree with an NICCD patient from China.

METHODSDNA was extracted from dried blood spots collected with filter papers from the proband and other 9 members in a NICCD pedigree from China, and then PCR amplification and agarose gel electrophoresis were performed, revealing two mutations preliminarily, which were further proved by Genescan, a procedure established in our laboratory already. Furthermore, the positions and characteristics of the mutations were finally confirmed by DNA sequencing.

RESULTSThe proband is a compound heterozygote of two mutations, 851-854del in exon 9 and 1638-1660dup in exon 16 of SLC25A13 gene. His mother and brother carry the former mutation, which predicts a frameshift and introduction of a stop codon at position 286, while his father, one aunt and her son carry the latter, resulting in a frameshift at codon 554, and introducing a stop codon at position 570.

CONCLUSIONA deletion mutation 851-854del in exon 9 and an insertion mutation 1638-1660dup in exon 16 of SLC25A13 gene were identified in the pedigree, providing reliable evidences for both diagnostic confirmation of the patient and the genetic counseling from other members in the pedigree.

Calcium-Binding Proteins ; deficiency ; genetics ; metabolism ; China ; Cholestasis ; etiology ; genetics ; Cholestasis, Intrahepatic ; genetics ; metabolism ; Citrullinemia ; complications ; genetics ; DNA Mutational Analysis ; Genetic Testing ; Hepatocytes ; Humans ; Infant ; Japan ; Liver Diseases ; genetics ; Male ; Membrane Transport Proteins ; Mitochondrial Membrane Transport Proteins ; genetics ; Mutation ; Organic Anion Transporters ; deficiency ; genetics ; Pedigree ; Urea Cycle Disorders, Inborn ; genetics

Citrin deficiency, autosomal recessive disorder, caused by mutation of SLC25A13 gene on chromosome 7q21.3 has two major phenotypes : neonatal intrahepatic chnlestatic hepatitis(N1CCD) and adult-onset type Ⅱ citrullinemia(CTLN2).So far, we have identified 52 SLC25A13 mutations and diagnosed the patients not only in Japan(166 CTLN2 and 238 NICCD) but also in other countries.We have detected 76 Chinese, 13 Korean and 15 Vietnamese patients with the same mutations as Japanese, and 13 patients(from Israel, UK, USA or Czech)with mutations different from those found in Japanese,indicating a wide distribution of citrin deficiency.DNA diagnoses of 13 known SLG25A13 mutations revealed that the carrier frequency was high in East Asian populations:Chinese(73/4 600=1/63) ,Japanese(21/1372=1/65) and Korean(25/2 690=1/108), suggesting that near by 100 000 East Asians are liomozygotes.It is important to find out patients with citrin deficiency,to treat them,and to prevent onset of severe CTLN2.

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is a kind of inborn errors of metabolism, with the main clinic manifestations of jaundice, hepatomegaly, and abnormal liver function indices. As a mitochondrial solute carrier protein, citrin plays important roles in aerobic glycolysis, gluconeogenesis, urea cycle, and protein and nucleotide syntheses. Therefore citrin deficiency causes various and complicated metabolic disturbances, such as hypoglycemia, hyperlactic acidemia, hyperammonemia, hypoproteinemia, hyperlipidemia, and galactosemia. This paper reported a case of NICCD confirmed by mutation analysis of SLC25A13, the gene encoding citrin. The baby (male, 6 months old) was referred to the First Affiliated Hospital with the complaint of jaundice of the skin and sclera, which it had suffered from for nearly 6 months. Physical examination showed obvious jaundice and a palpable liver 5 cm below the right subcostal margin. Liver function tests revealed elevated enzymatic activities, like GGT, ALP, AST, and ALT, together with increased levels of TBA, bilirubin (especially conjugated bilirubin), and decreased levels of total protein/albumin and fibrinogen. Blood levels of ammonia, lactate, cholesterol, and triglyceride were also increased, and in particular, the serum AFP level reached 319,225.70 microg/L, a extremely elevated value that has rarely been found in practice before. Tandem mass analysis of a dried blood sample revealed increased levels of free fatty acids and tyrosine, methionine, citrulline, and threonine as well. UP-GC-MS analysis of the urine sample showed elevated galactose and galactitol. The baby was thus diagnosed with suspected NICCD based on the findings. It was then treated with oral arginine and multiple vitamins (including fat-soluble vitamins A, D, E, and K), and was fed with lactose-free and medium-chain fatty acids enriched formula instead of breast feeding. After half a month of treatment, the jaundice disappeared, and the laboratory findings, including liver function indices, blood levels of ammonia, lactate and AFP, were returned to normal level. The baby was followed up for 6 months. It developed well, and the abnormal laboratory findings, including MS-MS and UP-GC-MS analysis results, have been corrected, except a slightly elevated lactate level sometimes. SLC25A13 gene mutation analysis for the patient revealed a compound heterozygote of mutation 851del4 and 1638ins23 and therefore NICCD was definitely diagnosed.
Calcium-Binding Proteins ; deficiency ; Cholestasis, Intrahepatic ; diagnosis ; etiology ; therapy ; Humans ; Infant ; Male ; Metabolism, Inborn Errors ; diagnosis ; etiology ; therapy ; Organic Anion Transporters ; deficiency

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

OBJECTIVENeonatal intrahepatic cholestasis caused by citrin deficiency (NICCD, OMIM #605814) is a novel autosomal recessive disease caused by mutations in the gene SLC25A13 that encodes for citrin, a liver-type aspartate/glutamate carrier located in the mitochondrial inner membrane. SLC25A13 was cloned in 1999 by Kobayashi et al at Kagoshima University in Japan, and until now, most of the NICCD patients reported in the world were Japanese. Most of the Chinese NICCD patients diagnosed by genetic analysis had the same SLC25A13 mutations as Japanese, however, in some cases, known mutations were not detected. This research aimed to identify novel SLC25A13 mutations in Chinese NICCD patients and to explore the experimental conditions for their genetic diagnosis.

METHODSGenomic DNA was extracted from blood samples of 3 NICCD patients from Taiwan (P757), Guangdong (P1194) and Hebei province (P1443) of China, respectively, and all the 18 exons and their flanking sequences of SLC25A13 gene were sequenced. Furthermore, the identified novel mutations were diagnosed by amplification with PCR, digestion with corresponding restriction endonuclease, and agarose gel electrophoresis.

RESULTSThree novel mutations identified in SLC25A13 gene of the 3 NICCD patients were an abnormal splicing IVS7-2A > G (P757), a missense A541D (c.1622C > A, P1194) and a nonsense R319X (c.955C > T, P1443). The PCR-restriction fragment length polymorphism (RFLP) procedures for their genetic diagnosis were also established, with specific fragments on electrophoresis after digestion of the PCR products with three different restriction endonucleases Msp I, Hpy188I and Taq I, respectively.

CONCLUSIONSSo far as we know, the three novel mutations in SLC25A13 gene of Chinese NICCD patients were first identified, suggesting that SLC25A13 mutation distributed in Chinese population is somewhat different from that in Japanese. Moreover, the PCR-RFLP diagnostic procedures established in this research provide valuable tools not only for the genetic diagnosis of NICCD but also for further molecular epidemiologic investigations in Chinese population.

Asian Continental Ancestry Group ; genetics ; Base Sequence ; Calcium-Binding Proteins ; deficiency ; Child, Preschool ; Cholestasis, Intrahepatic ; diagnosis ; etiology ; genetics ; Female ; Humans ; Infant ; Male ; Mitochondrial Membrane Transport Proteins ; genetics ; Molecular Sequence Data ; Mutation ; Organic Anion Transporters ; deficiency