Molecular basis of intrahepatic cholestasis

Intrahepatic cholestasis, or impairment of bile flow, is an important manifestation of inherited and acquired liver disease. In recent years, human genetic and molecular studies have identified several genes, the disruption of which results in cholestasis. ATP8B1 (FIC1), ABCB11 (BSEP), and ABCB4 (MDR3) are disrupted in forms of progressive familial intrahepatic cholestasis (PFIC) and related disorders. Mutations in BAAT, TJP2 (ZO-2), and EPHX1 have been identified in patients with hypercholanemia. A CLDN1 mutation was recently reported in patients with ichthyosis, leukocyte vacuoles, alopecia and sclerosing cholangitis (ILVASC), and North American Indian childhood cirrhosis (NAIC) is associated with a missense mutation in CIRH1A. Alagille syndrome patients carry mutations in JAG1, and mutations in VPS33B have been identified in patients with arthrogryposis, renal dysfunction and cholestasis syndrome (ARC). Identification of these genes, and characterization of the proteins they encode, is enhancing our understanding of the biology of the enterohepatic circulation in health and disease.     

ABCB1和CYP2C19基因多态性与动脉粥样硬化性脑梗死患者氯吡格雷疗效的相关性

目的:探讨在急性动脉粥样硬化性脑梗死患者中,不同ABCB1和CYP2C19基因型对氯吡格雷抗血小板疗效的影响。方法:纳入115例发病7 d内住院的急性动脉粥样硬化性脑梗死患者,根据CYP2C19基因型分为3组:快代谢型、中代谢型、慢代谢型;根据ABCB1基因型分为野生型和突变型。再根据ABCB1和CYP2C19两种基因突变的数量,将入组患者分为A组(两个基因均无突变)、B组(其中一个基因发生突变)和C组(两个基因均发生突变)。所有患者均予以卒中单元常规治疗,利用血栓弹力图仪(thromb elasto gram, TEG)检测患者服用氯吡格雷7 d后的血小板功能及血小板药物抑制率,并在患者入院时及服用氯吡格雷治疗7 d后进行神经功能评估,包括美国国立卫生研究院卒中量表(National Institute of Health Stroke Scale, NIHSS)及改良Rankin量表(modified rankin scale, mRS)。结果:CYP2C19基因快代谢型、中代谢型、慢代谢型分别有46例、48例(其中*1/*2 40例,*1/*3 8例)、21例(其中*2/*2 18例,*2/*3 3例);ABCB1野生型49例,突变型66例;A、B、C组患者分别有23例、50例、42例。不同ABCB1、CYP2C19基因型及含不同基因突变数量患者中,血小板药物抑制率、血小板功能及急性期神经功能变化情况差异均无统计学意义。结论:在本研究所纳入的急性动脉粥样硬化性脑梗死人群中,未发现ABCB1、CYP2C19基因多态性对氯吡格雷疗效的影响。     

ABCB4基因外显子12和23突变与妊娠期肝内胆汁淤积症的关系

目的：探讨ABCB4基因外显子12和23的突变与妊娠期肝内胆汁淤积症（ICP）发病的关系。方法：从31例ICP患者外周血标本中提取出基因组DNA，聚合酶链反应（PCR）扩增ABCB4基因外显子12和23，PCR产物经DNA序列测定检测突变情况。结果：31例ICP患者均扩增出ABCB4基因外显子12和23的靶基因片段，未见外显子12和23的缺失,DNA测序分析31例ICP患者ABCB4基因外显子12和23，未发现点突变。结论：ABCB4基因外显子12和23的突变与中国皖南地区的ICP发生无关或关联很小，皖南地区ICP患者中可能存在其他ABCB4基因突变热点。ABCB4基因的突变与中国人ICP发病的相关性仍应进行更大样本的研究和其他外显子的筛查。     

Molecular genetic analysis of long QT syndrome in Norway indicating a high prevalence of heterozygous mutation carriers

Mutations in the KCNQ1, HERG, SCN5A, minK and MiRP1 genes cause long QT syndrome (LQTS), of which there are two forms: the Romano Ward syndrome and the Jervell and Lange‐Nielsen syndrome. We have performed DNA sequencing of the LQTS‐associated genes in 169 unrelated patients referred for genetic testing with respect to Romano Ward syndrome and in 13 unrelated patients referred for genetic testing with respect to Jervell and Lange‐Nielsen syndrome. A total of 37 different mutations in the 5 genes, of which 20 were novel, were identified. Among patients with the most stringent clinical criteria of Romano Ward syndrome, a mutation was identified in 71?%. Twelve of the 13 unrelated patients referred for genetic testing with respect to Jervell and Lange‐Nielsen syndrome were provided with a molecular genetic diagnosis. Cascade genetic screening of 505 relatives of index patients with molecularly defined LQTS identified 251 mutation carriers. The observed penetrance was 41?%. Although caution must be exerted, the prevalence of heterozygotes for mutations in the LQTS‐associated genes in Norway could be in the range 1/100–1/300, based on the prevalence of patients with Jervell and Lange‐Nielsen syndrome.     

Effect of ABCB1 3435C>T Genetic Polymorphism on Pharmacokinetic Variables of Tacrolimus in Adult Renal Transplant Recipients: A Systematic Review and Meta-analysis

PurposeTacrolimus is the substrate of multidrug-resistance 1 (ABCB1). However, the effect of ABCB1 C3435T polymorphism on pharmacokinetic variables of tacrolimus is controversial in different studies. This meta-analysis was conducted to explore the relationship between ABCB1 3435C>T genetic polymorphism and pharmacokinetic variables of tacrolimus.MethodsA database search was conducted of PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov, as well as Chinese databases (SinoMed, Wan Fang, and China National Knowledge Infrastructure). We also scanned reference lists and corresponded with authors. The study explored the relationship between ABCB1 3435C>T genetic polymorphism and pharmacokinetic variables of tacrolimus stratified according to time of posttransplantation, ethnicity, methods of concentration measurement, and the initial doses of tacrolimus.FindingsSixteen studies were included in this meta-analysis. In the subgroup analysis, ABCB1 3435TT had a significantly lower weight-adjusted dose than ABCB1 3435CC, which was not observed in the ABCB1 3435CT group. The subgroup analysis then revealed that the tacrolimus concentration/weight-adjusted daily dose ratio of ABCB1 3435T carriers was significantly higher than that of the ABCB1 3435CC group at 1 and 6 months. Meanwhile, ABCB1 3435CT and TT both had a higher tacrolimus concentration/weight-adjusted daily dose ratio compared with ABCB1 3435CC.ImplicationsOur meta-analysis identified that the ABCB1 3435C>T genetic polymorphism affected the pharmacokinetic variables of tacrolimus in adult renal transplant recipients. However, individualized treatments based on genetic polymorphisms require further investigation.     

妊娠期肝内胆汁淤积症中ABCB4基因外显子23突变的研究

目的：探讨ABCB4基因外显子23点突变与妊娠期肝内胆汁淤积症（ICP）发病的关系。方法：采用聚合酶链反应（Pcrt）方法对31例妊娠期肝内胆汁淤积症患者扩增ABCB4基因外显子23．PCR产物进行DNA序列测定，以检测突变情况。结果：31例妊娠期肝内胆汁淤积症患者的血样标本。均扩增出ABCB4基因的外显子23。未发现外显子23的缺失。随机挑选20例标本测定外显子23的DNA序列。未发现点突变。结论：ABCB4基因外显子23与中国皖南地区的ICP发生无关或关联很小，皖南地区ICP患者中可能存在其他的ABCB4基因突变热点。ABCB4基因点突变与ICP发病的相关性仍应进行更大样本量的研究及其他突变热点的筛查。     

Frequent life-threatening laryngeal attacks in two Croatian families with hereditary angioedema due to C1 inhibitor deficiency harbouring a novel frameshift mutation in SERPING1

Objective: Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare autosomal dominant disease caused by mutations in the SERPING1 gene. It can affect many regions in the body, but potentially life-threatening laryngeal oedemas are of concern.

Methods: Twenty-three subjects from two families were recruited for clinical data evaluation and molecular analysis at General Hospital ?ibenik, Croatia.

Results: Decreased levels of C1 inhibitor were detected in 12 adult patients and three young asymptomatic persons. The same novel deletion of two nucleotides on exon 3 (c.74_75delAT) was identified in all of them. A history of laryngeal oedema was present in 10 patients (83%), and all patients reported laryngeal attacks at least once a year. The delay in diagnosis decreased noticeably from the first to the last generation.

Conclusions: We identified a novel causative mutation in SERPING1 in several affected members of two apparently unrelated families with a high frequency of laryngeal oedema. Molecular analysis of large C1-INH-HAE families will provide new insights on the genotype–phenotype relationship.

• Key messages

• Hereditary angioedema due to C1 inhibitor deficiency is a rare autosomal dominant disease caused by mutations in the SERPING1 gene, and laryngeal oedema is of concern because it can cause death by asphyxiation.

• A novel causative mutation in SERPING1, a deletion of two nucleotides on exon 3 (c.74_75delAT), was identified in several affected members of two apparently unrelated families with a high frequency of laryngeal oedema.

• Molecular analysis of large C1-INH-HAE families will provide new insights on the genotype–phenotype relationship because it appears that the mutation type may affect disease severity.

     

Hepatocyte nuclear factor 1B mutation in a Chinese family with renal cysts and diabetes syndrome: A case report

BACKGROUNDRenal cysts and diabetes (RCAD) syndrome is an autosomal dominant diabetic renal disease. Precise molecular diagnosis of RCAD syndrome has proven valuable for understanding its mechanism and personalized therapy.CASE SUMMARYA RCAD patient and her family were studied to investigate potential responsible genes by the whole exome sequencing (WES). Candidate pathogenic variants were validated by Sanger sequencing. The clinical characteristics of RCAD patient were collected from medical records. Unlike those typical RCAD patients, we observed renal manifestation and prediabetes phenotype, but not reproductive organ phenotype and hypomagnesaemia. A novel 7-bp deletion mutation in exon 4 of the hepatocyte nuclear factor 1B, {"type":"entrez-nucleotide","attrs":{"text":"NM_000458","term_id":"1519244814"}}NM_000458: c.882_888del (p.V294fs), was identified by WES and confirmed by Sanger sequencing. CONCLUSIONThis novel mutation identified in a Chinese family with RCAD syndrome might be the molecular pathogenic basis of this disorder.     

A new common mutation in the cardiac beta-myosin heavy chain gene in Finnish patients with hypertrophic cardiomyopathy

Abstract

Background. In the nationwide FinHCM Study including 306 Finnish patients with hypertrophic cardiomyopathy (HCM), we have previously identified two founder mutations in the alpha-tropomyosin (TPM1-D175N) and myosin-binding protein C (MYBPC3-Q1061X) genes, accounting for 18% of all cases.

Objective. To screen additional mutations, previously identified in eastern Finnish cohorts with HCM, in the FinHCM Study population.

Patients and methods. Ten mutations in the beta-myosin heavy chain gene (MYH7), TPM1, and MYBPC3 were screened.

Results. MYH7-R1053Q was found in 17 of 306 patients (5.6%). No carriers of MYH7-R719W or N696S were found. A novel TPM1-D175G mutation was found in a single patient. MYBPC3 mutations were found in 14 patients: IVS5-2A-C in two, IVS14-13G-A in two, K811del in six, and A851insT in four patients. Altogether, a HCM-causing mutation was identified in 32 patients, accounting for 10.5% of all cases. In addition, two MYBPC3 variants R326Q and V896M with uncertain pathogenicity were found in eight and in 10 patients, respectively.

Conclusion. Combining the present findings with our previous results, a causative mutation was identified in 28% of the FinHCM cohort. MYH7-R1053Q was the third most common mutation, and should be screened in all new cases of HCM in Finland.     

SF3B1 mutation is a rare event in Chinese patients with acute and chronic myeloid leukemia

ObjectiveSomatic mutations of SF3B1 gene have recently been identified in myelodysplastic syndrome and chronic lymphocytic leukemia. The frequency and clinical relevance of SF3B1 mutations have been rarely studied in acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). The present study was aimed to analyze the frequency of SF3B1 mutations in AML and CML.Designs and methodsHigh-resolution melting analysis (HRMA) was established to detect the mutation hotspots (codon E622, H662, K666, and K700) of SF3B1 gene in 275 AML and 81 CML patients.ResultsHeterozygous SF3B1 mutations were detected in three AML patients by HRMA. Direct DNA sequencing identified one K666T, one K666N and one K700E mutations. All three AML patients had normal karyotypes. One case also had NPM1 and DNMT3A mutations, one had FLT3 internal tandem duplication and DNMT3A mutations, and the other had NPM1 mutation. No SF3B1 mutations were detected in CML patients.ConclusionsSF3B1 mutation is a rare molecular event in Chinese AML and CML patients.     

PDZD7 is a modifier of retinal disease and a contributor to digenic Usher syndrome

Usher syndrome is a genetically heterogeneous recessive disease characterized by hearing loss and retinitis pigmentosa (RP). It frequently presents with unexplained, often intrafamilial, variability of the visual phenotype. Although 9 genes have been linked with Usher syndrome, many patients do not have mutations in any of these genes, suggesting that there are still unidentified genes involved in the syndrome. Here, we have determined that mutations in PDZ domain–containing 7 (PDZD7), which encodes a homolog of proteins mutated in Usher syndrome subtype 1C (USH1C) and USH2D, contribute to Usher syndrome. Mutations in PDZD7 were identified only in patients with mutations in other known Usher genes. In a set of sisters, each with a homozygous mutation in USH2A, a frame-shift mutation in PDZD7 was present in the sister with more severe RP and earlier disease onset. Further, heterozygous PDZD7 mutations were present in patients with truncating mutations in USH2A, G protein–coupled receptor 98 (GPR98; also known as USH2C), and an unidentified locus. We validated the human genotypes using zebrafish, and our findings were consistent with digenic inheritance of PDZD7 and GPR98, and with PDZD7 as a retinal disease modifier in patients with USH2A. Pdzd7 knockdown produced an Usher-like phenotype in zebrafish, exacerbated retinal cell death in combination with ush2a or gpr98, and reduced Gpr98 localization in the region of the photoreceptor connecting cilium. Our data challenge the view of Usher syndrome as a traditional Mendelian disorder and support the reclassification of Usher syndrome as an oligogenic disease.     

Role of the fractalkine receptor CX3CR1 polymorphisms V249I and T280M as risk factors for early‐onset coronary artery disease in patients with no classic risk factors

Objectives. CX3CR1 is a monocyte chemokine receptor and adhesion molecule. Two CX3CR1 mutations, V249I and T280M, reportedly decrease coronary artery disease (CAD) risk independent of established risk factors. An I249 protective effect is attributed to reducing CX3CR1 binding to fractalkine, its ligand. Material and methods. We examined the frequencies of V249I and T280M among early‐onset CAD patients (G1; n = 149; <50 years), late‐onset CAD patients (G2; n = 150; >65 years) and healthy controls (HC; n = 149, 47–93 years) without known CAD risk factors. We compared plasma total cholesterol (TC)/high density lipoprotein‐C (HDL‐C) and apolipoprotein B (APOB)/apolipoprotein AI (APOAI) ratios among the groups and mutation carriers and non‐carriers, and the prevalence of the mutations in G1 and G2 patients with multiple coronary vessel disease (MVD) and myocardial infarction (MI). Results. G1 patients had non‐significantly lower frequencies of I249 versus (vs.) G2 or controls (G1; 51 %, G2: 61 %, controls: 58 %, p = 0.19), with no difference in T280M (p = 0.8). TC/HDL‐C and APOB/APOAI ratios were significantly higher in G1 patients vs. G2 and controls (p<0.0001) independently of either mutation. More G2 patients had MVD than younger ones (p<0.0001); however, more G1 patients were homozygous for V249 compared to G2 patients, who more often had the I249 allele (p<0.02). There was no such association with T280M (p = 0.38). Although more G1 patients had MI, this was not mutation related. Conclusions. There were significantly higher lipid ratios in G1 compared to G2 and HC (G1>G2>HC), but not in mutation prevalence. I249 mutation was associated with MVD in older patients, while V249 homozygosity was associated with the early‐onset CAD. Neither allele affected MI or lipid levels.     

Hereditary angioedema due to C1-inhibitor deficiency in Macedonia: clinical characteristics,novel SERPING1 mutations and genetic factors modifying the clinical phenotype

Objective: Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare disease, characterized by swellings. We aimed to characterize on a clinical and molecular basis C1-INH-HAE patients in the Republic of Macedonia.

Results: All 15 patients from six unrelated families were diagnosed with C1-INH-HAE type I, with a mean age of symptom onset of 11 years and an average delay of diagnosis of seven years. Patients reported on average 31 angioedema attacks/year, with a median clinical severity score (CSS) of 7. We identified three known mutations and two new mutations (c.813_818delCAACAA and c.1488T?>?G) that were reported for the first time. To address the genotype-phenotype association, a pooled analysis including 78 C1-INH-HAE south-eastern European patients was performed, with additional analysis of F12-46C/T and KLKB1-428G/A polymorphisms. We demonstrated that patients with nonsense and frameshift mutations, large deletions/insertions, splicing defects and mutations at Arg444 exhibited an increased CSS compared with missense mutations, excluding mutations at Arg444. In addition, the CC F12-46C/T polymorphism was suggestive of earlier disease onset.

Discussion: Genetic analysis helped identify the molecular basis of C1-INH-HAE given that causative mutations in SERPING1 were detected in all patients, including an infant before the appearance of clinical symptoms. We identified two novel mutations and further corroborated the genotype-phenotype relationship, wherein mutations with a clear effect on C1-INH function predispose patients to a more severe disease phenotype and CC F12-46C/T predisposes patients to earlier disease onset.

• KEY MESSAGES

• ??In the present nationwide study, we aimed to characterize on a clinical and molecular basis patients with hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) in the Republic of Macedonia.

• ??Causative mutations in SERPING1 were detected in all 15 C1-INH-HAE patients from six Macedonian families, including an infant, before the appearance of clinical symptoms.

• ??We identified three known mutations and two novel mutations (c.813_818delCAACAA and c.1488T?>?G). These findings further corroborated the genotype-phenotype relationship, wherein mutations with a clear effect on C1-INH function predispose patients to a more severe disease phenotype and the CC F12-46C/T polymorphism predisposes patients to earlier disease onset.

     

白血病干/祖细胞相关基因表达在急性白血病中的临床意义

本研究旨在检测白血病干/祖细胞(LSPC)相关基因ABCB1、BMI-1、HOXB4在急性白血病患者骨髓中的表达,并探讨其在急性白血病中的临床意义。采集41例初治急性白血病患者的骨髓、16例缓解期患者的骨髓及10例非恶性血液病患者骨髓标本(作为对照)。采用SYBR Green相对定量RT-PCR法检测ABCB1、BMI-1、HOXB4基因的表达水平,并分析它们与急性白血病疗效、预后的关系。结果表明,ABCB1、BMI-1、HOXB4在对照组均无表达,在初治组相对表达量分别为4.26±2.26、3.72±1.91、3.74±2.38;而在缓解标本组分别为2.14±1.47、2.07±0.99、1.47±0.89,均明显低于初治组(p<0.05);正规化疗2个疗程内能够获得完全/部分缓解的患者的基因相对表达量分别为1.77±1.29、2.09±1.26、1.78±1.49,明显低于未缓解的难治病例(分别为7.23±1.78、3.96±0.92、4.48±2.57)(p<0.01)。单因素分析发现,各个基因高表达患者的白血病干/祖细胞免疫表型(CD34+CD38-CD96+和CD34+CD38-CD123+)表达阳性的比例及出现高白细胞(≥30×109/L)的几率均高于低表达患者,差异显著(p<0.05);而综合分析各个基因的表达,上述变化的p值均小于单因素分析p值,差异更显著(p<0.01)。结论:LSPC相关基因(ABCB1、BMI-1、HOXB4)表达与LSPC免疫表型呈相关性,在急性白血病患者发病初期表达增高,缓解后其表达水平明显下降;表达高者易出现高白细胞,化疗效果差,缓解率低。综合多指标分析可能是一种更好地临床评估疗效和预后的方法。     

Association of ABCB1, CYP3A4*18B and CYP3A5*3 genotypes with the pharmacokinetics of tacrolimus in healthy Chinese subjects: a population pharmacokinetic analysis

What is known and Objective: Tacrolimus (TAC) is metabolized mainly by the CYP3A subfamily and extruded into the intestine by P‐glycoprotein, which is encoded by the ABCB1 gene. Several studies have suggested that the CYP3A5*3 genotype influenced the pharmacokinetics (PK) of TAC. The CYP3A4*18B and CYP3A5*3 alleles are clinically important in Chinese subjects because of their relatively high frequency. The present study aimed at evaluating the effects of ABCB1 (C1236T‐G2677T/A‐C3435T), CYP3A4*18B and CYP3A5*3 genetic polymorphisms on TAC PK in healthy Chinese subjects. Methods: Data were obtained from a comparative bioavailability study of oral TAC formulations (n = 22). TAC whole blood concentrations were measured by LC‐MS/MS. Genetic polymorphisms were determined using a direct sequencing method. Nonlinear mixed‐effects modelling (NONMEM) was performed to assess the effect of genotypes and demographics on TAC PKs. Results and Discussion: Both CYP3A4*18B and CYP3A5*3 polymorphisms affected the TAC PK, whereas ABCB1 genetic polymorphisms and other demographic characteristics did not. The combined genotypes of CYP3A4*18B and CYP3A5*3 had a greater impact than either genotype alone, and they were estimated to account for 28·4% of the inter‐subject variability of apparent clearance (CL/F) by NONMEM. The CL/F in subjects with CYP3A4*1/*1‐CYP3A5*3/*3 was 10·3 L/h and was 48·5% in those not carrying CYP3A4*1/*1‐CYP3A5*3/*3. What is new and Conclusion: This is the first study to extensively explore the influence of CYP3A4*18B, CYP3A5*3 and ABCB1 genetic polymorphisms on TAC PK in healthy Chinese subjects. The results demonstrated that subjects with a combined genotype of CYP3A4*1/*1‐CYP3A5*3/*3 may require lower TAC doses to achieve target concentration levels and further investigation is needed in larger populations to confirm the clinical benefits.     

A novel mutation of GATA4 in a familial atrial septal defect

BackgroundPrevious studies have identified that mutations in a few genes, including T-BOX5, NKX2-5, EVC and GATA4, are associated with atrial septal defect (ASD).MethodsA family of three generations with 4 members who were affected with ASD was investigated. To exclude the presence of any sub-microscopic chromosomal imbalance, high-resolution 1M array-based comparative genomic hybridization (aCGH) was performed. SNaPShot was used to certify the specificity of the finding mutation in the other family members. The coding region of GATA4 and NKX2-5 genes was screened by sequencing in another 30 cases including 10 cases of ventricular septal defect (VSD), 10 cases of atrial septal defect (ASD), 8 cases of VSD combined with ASD and 2 cases of atrioventricular septal defects (AVSD).ResultsNo pathogenic copy number variant was detected by aCGH in the four affected family members with ASD. A novel non-synonymous variant, c.839C>T (T280M) in GATA4, was identified and segregated with all the ASD patients within this Chinese family. Such mutation was absent in other family members or present among sporadic CHD patients. In addition, we identified a non-synonymous variant in the NKX2-5 gene (P257A) associated with one congenital heart disease patient with VSD. Both mutations were not identified among healthy controls.ConclusionT280M mutation of GATA4 is suggested to be associated with ASD in this Chinese family.     

Genetics of gallstone disease

Background

Gallstone disease (GD) belongs to the most frequent disorders in gastroenterology and causes high costs in our health‐care systems. Gallstones are uncommon in children but frequent in adults, in particular in women, and are triggered by exogenous risk factors. Here, we summarize the current knowledge concerning the contribution of inherited predisposition to gallstone risk.

Design

In this review, we present the current data and recent research on the genetics of gallstone disease.

Results

Several GD‐predisposing gene variants have been reported, with most prominent effects being conferred by a common variant (p.D19H) of the hepatic and intestinal cholesterol transporter ABCG5/G8. A smaller group of patients might develop gallstones primarily due low phosphatidylcholine concentrations in bile as a result of loss‐of‐function mutations of the ABCB4 transporter (low phospholipid‐associated cholelithiasis syndrome). Regardless of the origin, the risk factors for gallstones lead to the supersaturation of bile with insoluble compounds, in particular cholesterol. As result, cholesterol stones develop and present the most frequent type of gallstones. Laparoscopic cholecystectomy with low morbidity and mortality is currently the most common and effective method for the therapy of symptomatic gallbladder stones.

Conclusions

Gallstone disease represents a multifactorial condition and previous studies have identified the major genetic contributors to gallstone formation. The increasing knowledge about the pathomechanisms of hepatobiliary metabolism and GD as well as the identification of additional risk factors might help to overcome the current invasive therapy by specific lifestyle intervention and precise molecular treatment.     

Association of genotypes and haplotypes of multi-drug transporter genes ABCB1 and ABCG2 with clinical response to imatinib mesylate in chronic myeloid leukemia patients

The introduction and success of imatinib mesylate (IM) has become a paradigm shift in chronic myeloid leukemia (CML) treatment. However, the high efficacy of IM has been hampered by the issue of clinical resistance that might due to pharmacogenetic variability. In the current study, the contribution of three common single nucleotide polymorphisms (SNPs) of ABCB1 (T1236C, G2677T/A and C3435T) and two SNPs of ABCG2 (G34A and C421A) genes in mediating resistance and/or good response among 215 CML patients on IM therapy were investigated. Among these patients, the frequency distribution of ABCG2 421 CC, CA and AA genotypes were significantly different between IM good response and resistant groups (P = 0.01). Resistance was significantly associated with patients who had homozygous ABCB1 1236 CC genotype with OR 2.79 (95%CI: 1.217–6.374, P = 0.01). For ABCB1 G2677T/A polymorphism, a better complete cytogenetic remission was observed for patients with variant TT/AT/AA genotype, compared to other genotype groups (OR = 0.48, 95%CI: 0.239–0.957, P = 0.03). Haplotype analysis revealed that ABCB1 haplotypes (C₁₂₃₆G₂₆₇₇C₃₄₃₅) was statistically linked to higher risk to IM resistance (25.8% vs. 17.4%, P = 0.04), while ABCG2 diplotype A₃₄A₄₂₁ was significantly correlated with IM good response (9.1% vs. 3.9%, P = 0.03). In addition, genotypic variant in ABCG2 421C>A was associated with a major molecular response (MMR) (OR = 2.20, 95%CI: 1.273–3.811, P = 0.004), whereas ABCB1 2677G>T/A variant was associated with a significantly lower molecular response (OR = 0.49, 95%CI: 0.248–0.974, P = 0.04). However, there was no significant correlation of these SNPs with IM intolerance and IM induced hepatotoxicity. Our results suggest the usefulness of genotyping of these single nucleotide polymorphisms in predicting IM response among CML patients.     

Mutation-based diagnostic testing for primary hyperoxaluria type 1: survey of results

ObjectivesTo test for specific mutations in the alanine:glyoxylate aminotransferase (AGT) gene, in order to diagnose primary hyperoxaluria type 1 (PH1).Design and methodsSamples of liver and/or DNA from 81 patients were submitted to our laboratory for diagnostic testing for PH1. Using a panel of selected mutations, DNA was examined in 64 cases, of which 36 had the diagnosis of PH1 confirmed by liver AGT assay. DNA sequencing was employed if mutation testing revealed only one mutation.ResultsIdentification of 100% of the mutations in the AGT-confirmed samples led to the development of a focused testing panel currently involving 4 common mutations, 7 mutations recurring at lower frequency and 5 with apparent ethnic associations.ConclusionsThis mutation panel alone would have identified the two causative mutations in 64% of the PH1 samples.     

Association of ABCB1 Polymorphisms With the Efficacy of Ondansetron in Chemotherapy-induced Nausea and Vomiting

Purpose

Resistance to the antiemetic ondansetron is still a major problem resulting in discomfort and poor compliance with chemotherapy in acute myeloid leukemia (AML) patients. Based on our hypothesis that this clinical resistance to ondansetron is associated with ABCB1 genetic polymorphisms, we investigated whether ABCB1 gene variations affect the efficacy of ondansetron in chemotherapy-induced nausea and vomiting.

Methods

AML patients (n = 215) treated for 3 days with high-dose cytarabine were enrolled in this study. Thirty minutes before the beginning of chemotherapy, 8 mg ondansetron was administered intravenously, followed by 24 mg by continuous infusion and 8 mg intravenously, once per day, until 2 days after chemotherapy. Chemotherapy-induced nausea and vomiting occurrence in the acute and delayed phases was calculated. ABCB1 and CYP2D6 polymorphisms were analyzed by allele-specific matrix-assisted laser desorption. Basic clinical characteristics of the AML patients were collected from medical records.

Findings

No differences in genotype distribution frequencies of ABCB1 polymorphisms and haplotypes were observed in patients with different CYP2D6-predicted phenotypes. During the acute phase, patients with the CG haplotype (C3435T and G2677T) were associated with a high risk of grade 3/4 nausea and vomiting (P = 0.003 and P = 0.026, respectively). After adjustment for age, sex, smoking status, alcohol drinking status, body surface area, body mass index, and Eastern Cooperative Oncology Group−Performance Status, multivariate survival analysis implicated the CG haplotype as a predictive marker of the risk of grade 3/4 chemotherapy-induced nausea and vomiting in AML patients (P = 0.003 and P = 0.039, respectively). In addition, a significant association between the 3435CC genotype and grade 3/4 vomiting in AML patients was observed (P = 0.016). However, no association between these ABCB1 gene polymorphisms and ondansetron efficacy was found in the delayed phase.

Implications

These findings suggest that ABCB1 gene polymorphisms are associated with antiemetic efficacy of ondansetron in the acute phase after high-dose cytarabine chemotherapy in AML patients.