Large-scale search of SNPs for type 2 DM susceptibility genes in a Japanese population

Effects of a dietary intervention with Mediterranean vs lacto-ovo vegetarian diets on HDL function: Results from the CARDIVEG study

BACKGROUND AND AIM

HDL-cholesterol efflux capacity (CEC) has been shown to be a better cardiovascular (CVD) risk marker than serum HDL concentration. Several foods and nutrients have been shown to improve HDL functions, however no effective dietetic nor pharmacological strategy is available to increase CEC. This study aims to evaluate the possible effect of Mediterranean diet (MD) and lacto-ovo-vegetarian diet (VD) on HDL function in a group of clinically healthy subjects at low-to-moderate CVD risk.

METHODS AND RESULTS

Thirty apparently healthy subjects with a low-to-moderate cardiovascular risk profile (21 F; mean age: 51.3 ± 9.7 years) were randomly assigned to a 3-month MD or VD diet and then crossed. Participants on VD showed a reduction in total HDL CEC by 8.99% (p < 0.001) as well as a reduction in ABCA1 mediated-CEC by 18.62% (p < 0.001) compared to participants on MD. Regarding CEC mediated by aqueous diffusion, no significant changes were observed after treatment with either diet. Finally, a significant positive association between CEC mediated by the ABCA1 transporter and adiponectin was found (r = 0.462; p = 0.010).

CONCLUSION

The results of this study suggest that HDL activity in promoting cholesterol efflux and thereby reducing the concentration of pro-atherogenic lipoproteins was more effective in participants undergoing MD than VD. Based on these findings, the MD could be considered a better therapeutic strategy for cardiovascular prevention than VD.

CLINICAL TRIAL REGISTRATION URL

http://www.

CLINICALTRIALS

gov. Unique identifier: NCT02641834.

Diabetes and Genetics: A Relationship Between Genetic Risk Alleles, Clinical Phenotypes and Therapeutic Approaches

Unveiling human genome through successful completion of Human Genome Project and International HapMap Projects with the advent of state of art technologies has shed light on diseases associated genetic determinants. Identification of mutational landscapes such as copy number variation, single nucleotide polymorphisms or variants in different genes and loci have revealed not only genetic risk factors responsible for diseases but also region(s) playing protective roles. Diabetes is a global health concern with two major types - type 1 diabetes (T1D) and type 2 diabetes (T2D). Great progress in understanding the underlying genetic predisposition to T1D and T2D have been made by candidate gene studies, genetic linkage studies, genome wide association studies with substantial number of samples. Genetic information has importance in predicting clinical outcomes. In this review, we focus on recent advancement regarding candidate gene(s) associated with these two traits along with their clinical parameters as well as therapeutic approaches perceived. Understanding genetic architecture of these disease traits relating clinical phenotypes would certainly facilitate population stratification in diagnosing and treating T1D/T2D considering the doses and toxicity of specific drugs.

The Play of Genes and Non-genetic Factors on Type 2 Diabetes

Diabetes has been a disease of public health concern for a number of decades. It was in the 1930s when scientists made an interesting discovery that the disease is actually divided into two types as some patients were insensitive to insulin treatment then. Type 2 Diabetes which happens to be the non-insulin dependent one is the most common form of the disease and is caused by the interaction between genetic and non-genetic factors. Despite conflicting results, numerous studies have identified genetic and non-genetic factors associated with this common type of diabetes. This review has summarized literature on some genes and non-genetic factors which have been identified to be associated with Type 2 diabetes. It has sourced literature from PubMed, Web of Science and Medline without any limitation to regions, publication types, or languages. The paper has started with the introduction, the play of non-genetic factors, the impact of genes in general, and ended with the interaction between some genes and environmental factors.

ATP-binding cassette sub-family a member1 gene mutation improves lipid metabolic abnormalities in diabetes mellitus

Background

Patients with diabetes mellitus were often accompanied with hyperlipidemia. ATP-binding cassette sub-family A member1 (ABCA1) promotes the efflux of lipids and thereby mediates the metabolism of cholesterol. The aim of our study was to determine the associations of ABCA1 gene polymorphisms with the risks of diabetes mellitus and dyslipidemia in diabetic patients.

Methods

We retrieved literature about the relationship between ABCA1 gene polymorphisms (C69T and R230C) and the risk of diabetes through PubMed, Web of Science, EMBASE, Wanfang Database, China National Knowledge Infrastructure (CNKI) and Cochrane database. Weighted mean difference (WMD) and odds ratio (OR) were used to compare continuous and dichotomous variables, respectively, accompanied by their 95% confidence interval (CI).

Results

A total of 1746 diabetic patients and 1292 non-diabetic controls were enrolled. All subjects were Caucasians. ABCA1 R230C T allele was significantly associated with reduced the risk of diabetes (OR = 0.75, 95% CI = 0.57–0.98, P = 0.04). There was no association of ABCA1 C69T gene polymorphisms with the risk of diabetes. However, subgroup analyses showed that the ABCA1 C69T gene mutation significantly reduced the risk of hypertriglyceridemia in diabetic patients as compared with that in non-diabetic subjects (dominant model: WMD =0.66, 95% CI = 0.52–0.8, P < 0.0001; recessive model: WMD = 0.47, 95%CI = 0.11–0.83, P = 0.01).

Conclusions

ABCA1 R230C T allele gene mutation is a protective in decreasing the risk of diabetes in Caucasians and ABCA1 C69T gene mutation markedly influences the level of lipid metabolism in diabetic patients.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-0998-3) contains supplementary material, which is available to authorized users.

Association of ATP binding cassette transporter 1 (ABCA 1) gene polymorphism with type 2 diabetes mellitus (T2DM) in Bangladeshi population

AIMS

ATP-binding cassette transporter 1 (ABCA1) gene polymorphism has been reported as one of the genetic risk factors for T2DM in various populations with conflicting results. The aim of this study is to investigate the association of ABCA1 C69T polymorphism and lipid profile with T2DM in Bangladeshi population.

MATERIALS AND METHODS

A total of 102 T2DM subjects and 98 healthy controls were recruited and their genotypes for ABCA1 gene polymorphisms were determined based on the PCR-RFLP technique. Serum lipid profiles (total cholesterol, HDL-C, LDL-C and TG) were also estimated by using standard methods.

RESULTS

ABCA 1 (C69T) genotypes frequencies were estimated. The percentages of CC, CT and TT genotypes at 69 position of ABCA1 gene were 31.63%, 58.16% and 10.21% in control as well as 22.54%, 69.60% and 7.86% in diabetes group respectively. Significant association was not found between ABCA1 (C69T) genotypes and T2DM in Bangladeshi population (Odd Ratio: 1.67; 95% Confidence Interval: 0.88 to 3.19 for CT genotype and Odd Ratio: 1.07; Confidence Interval: 0.36 to 3.16 for TT genotype; p > 0.05). Serum lipid profiles were not associated with T2DM.

CONCLUSION

ABCA1 gene polymorphism might not be a genetic risk factor for T2DM subjects among Bangladeshis. We did not find a relationship between genotypes and lipid concentrations in our two groups. Study with a larger sample size will help us to understand the relationship of ABCA1 C69T genotype and lipid profile with T2DM.

ABCG2 variant has opposing effects on onset ages of Parkinson's disease and gout

Uric acid (urate) has been suggested to play a protective role in Parkinson's disease onset through its antioxidant activity. Dysfunction of ABCG2, a high-capacity urate exporter, is a major cause for early-onset gout based on hyperuricemia. In this study, the effects of a dysfunctional ABCG2 variant (Q141K, rs2231142) were analyzed on the ages at onset of gout patients (N = 507) and Parkinson's disease patients (N = 1015). The Q141K variant hastened the gout onset (P = 0.0027), but significantly associated with later Parkinson's disease onset (P = 0.025). Our findings will be helpful for development of more effective prevention of Parkinson's disease.

Common variant of ALPK1 is not associated with gout: a replication study

Gout is one of the most kinds of common inflammatory arthritis as a consequence of hyperuricemia. Alpha-protein kinase 1 (ALPK1) gene locates in a gout-susceptibility locus on chromosome 4q21-31, and encodes ALPK1 protein which plays a pivotal role in the phosphorylation of myosin 1. In the previous genetic study of Taiwanese populations, 3 single nucleotide polymorphisms (SNPs), rs11726117, rs231247 and rs231253, in ALPK1 gene were reported to have a significant association with gout. However, no replication study has been performed to confirm this association. Therefore, we first conducted a replication study with clinically defined gout patients in a different population. Linkage disequilibrium (LD) analyzes of the 3 SNPs in ALPK1 revealed that these SNPs are in strong LD in a Japanese population. Among the 3 SNPs of ALPK1, rs11726117 (M861T) is the only missense SNP. Therefore, rs11726117 was genotyped in a Japanese population of 903 clinically defined gout cases and 1,302 controls, and was evaluated for a possible association with gout. The minor allele frequencies of rs11726117 were 0.26 and 0.25 in the case and control groups, respectively. The association analysis has not detected a significant association between rs11726117 and gout susceptibility in a Japanese population (p = 0.44). Because ABCG2, a major causative gene for gout, also locates in the gout-susceptibility locus on chromosome 4q, these findings suggest that among genes in a gout-susceptibility locus, not ALPK1 but ABCG2 could be important as a gout-susceptible gene.

ABCA1 C69T gene polymorphism and risk of type 2 diabetes mellitus in a Saudi population

Type 2 diabetes mellitus (T2DM) is a disease induced by complex interactions between environmental factors and certain genetic factors. Genetic variants in the Adenosine Binding Cassette Transporter Proteins 1 (ABCA1) have been associated with abnormalities of serum lipid levels of high-density lipoprotein (HDL-C). Decreased serum levels of HDL-C have often been observed in T2DM cases, and this condition has been considered to be involved in the mechanism of insulin resistance (IR). Therefore, we investigated possible association between ABCA1 C69T gene polymorphism and T2DMin a Saudi population. This study was carried out with 380 healthy control subjects and 376 T2DM patients. Genotyping of ABCA1 C69T polymorphism was carried out by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism technique. We observed that the frequency of the T allele of the ABCA1 C69T gene was significantly higher in healthy subjects compared to T2DMpatients (0.28 vs 0.45; p less than 0.0001; OR (95 percent CI) = 0.4624 (0.3732-0.5729), and therefore the T allele may be a protective factor against T2DM in the Saudi population.

Decreased extra-renal urate excretion is a common cause of hyperuricemia

ABCG2, also known as BCRP, is a high-capacity urate exporter, the dysfunction of which raises gout/hyperuricemia risk. Generally, hyperuricemia has been classified into urate 'overproduction type' and/or 'underexcretion type' based solely on renal urate excretion, without considering an extra-renal pathway. Here we show that decreased extra-renal urate excretion caused by ABCG2 dysfunction is a common mechanism of hyperuricemia. Clinical parameters, including urinary urate excretion, are examined in 644 male outpatients with hyperuricemia. Paradoxically, ABCG2 export dysfunction significantly increases urinary urate excretion and risk ratio of urate overproduction. Abcg2-knockout mice show increased serum uric acid levels and renal urate excretion, and decreased intestinal urate excretion. Together with high ABCG2 expression in extra-renal tissues, our data suggest that the 'overproduction type' in the current concept of hyperuricemia be renamed 'renal overload type', which consists of two subtypes-'extra-renal urate underexcretion' and genuine 'urate overproduction'-providing a new concept valuable for the treatment of hyperuricemia and gout.

Cholesterol efflux via ATP-binding cassette transporter A1 (ABCA1) and cholesterol uptake via the LDL receptor influences cholesterol-induced impairment of beta cell function in mice

AIMS/HYPOTHESIS

Cellular cholesterol accumulation is an emerging mechanism for beta cell dysfunction in type 2 diabetes. Absence of the cholesterol transporter ATP-binding cassette transporter A1 (ABCA1) results in increased islet cholesterol and impaired insulin secretion, indicating that impaired cholesterol efflux leads to beta cell dysfunction. In this study, we aimed to determine the role of the LDL receptor (LDLr) in islet cholesterol uptake and to assess the contributions of cholesterol uptake compared with efflux to islet cholesterol levels.

METHODS

Islet cholesterol and beta cell function were assessed in mice lacking LDLr (Ldlr(-/-)), or apolipoprotein E (Apoe(-/-)), as well as in mice with beta-cell-specific deficiency of Abca1 crossed to Ldlr(-/-) mice.

RESULTS

Hypercholesterolaemia resulted in increased islet cholesterol levels and decreased beta cell function in Apoe(-/-) mice but not in Ldlr(-/-) mice, suggesting that the LDL receptor is required for cholesterol uptake leading to cholesterol-induced beta cell dysfunction. Interestingly, when wild-type islets with functional LDL receptors were transplanted into diabetic, hypercholesterolaemic mice, islet graft function was normal compared with Ldlr(-/-) islets, suggesting that compensatory mechanisms can maintain islet cholesterol homeostasis in a hypercholesterolaemic environment. Indeed, transplanted wild-type islets had increased Abca1 expression. However, lack of the Ldlr did not protect Abca1(-/-) mice from islet cholesterol accumulation, suggesting that cholesterol efflux is the critical regulator of cholesterol levels in islets.

CONCLUSIONS/INTERPRETATION

Our data indicate that islet cholesterol levels and beta cell function are strongly influenced by LDLr-mediated uptake of cholesterol into beta cells. Cholesterol efflux mediated by ABCA1, however, can compensate in hypercholesterolaemia to regulate islet cholesterol levels in vivo.

Cholesterol in islet dysfunction and type 2 diabetes

Type 2 diabetes (T2D) frequently occurs in the context of abnormalities of plasma lipoproteins. However, a role for elevated levels of plasma cholesterol in the pathogenesis of this disease is not well established. Recent evidence suggests that alterations of plasma and islet cholesterol levels may contribute to islet dysfunction and loss of insulin secretion. A number of genes involved in lipid metabolism have been implicated in T2D. Recently an important role for ABCA1, a cellular cholesterol transporter, has emerged in regulating cholesterol homeostasis and insulin secretion in pancreatic beta cells. Here we review the impact of cholesterol metabolism on islet function and its potential relationship to T2D.

Effects of ABCA1 variants on rosiglitazone monotherapy in newly diagnosed type 2 diabetes patients

AIM

The aim of the present study was to investigate the relationship between R219K, M883I, and R1587K variants of the ATP-binding cassette transporter subfamily A number 1 (ABCA1) gene and response to rosiglitazone treatment in newly diagnosed patients with type 2 diabetes.

METHODS

A total of 105 diabetic patients with no history of antihyperglycemia medication were treated with rosiglitazone (4 or 8 mg daily) for 48 weeks. Three non-synonymous variants R219K, M883I, and R1587K, were genotyped in all patients.

RESULTS

Ninety-three patients completed the entire study. The R219K variant of ABCA1 had an effect on rosiglitazone response with the per-allele odds ratio of 2.04 for treatment failure (P<0.05). The RR homozygotes had a better improvement in indicators of insulin sensitivity, as determined by a significantly greater decrease in the homeostasis model assessment index of insulin resistance (-2.39+/-0.46 vs -0.69+/-0.51, P<0.05). No genotype-phenotype association was detected for M883I and R1587K.

CONCLUSION

The R219K variant of ABCA1 was associated with the therapeutic effect of rosiglitazone. The RR homozygotes had a better response to rosiglitazone treatment in terms of insulin sensitivity improvement than minor K allele carriers. Neither the M883I nor R1587K variant of the ABCA1 gene was associated with rosiglitazone response.

ERCC4 associated with breast cancer risk: a two-stage case-control study using high-throughput genotyping

The failure of linkage studies to identify further high-penetrance susceptibility genes for breast cancer points to a polygenic model, with more common variants having modest effects on risk, as the most likely candidate. We have carried out a two-stage case-control study in two European populations to identify low-penetrance genes for breast cancer using high-throughput genotyping. Single-nucleotide polymorphisms (SNPs) were selected across preselected cancer-related genes, choosing tagSNPs and functional variants where possible. In stage 1, genotype frequencies for 640 SNPs in 111 genes were compared between 864 breast cancer cases and 845 controls from the Spanish population. In stage 2, candidate SNPs identified in stage 1 (nominal P < 0.01) were tested in a Finnish series of 884 cases and 1,104 controls. Of the 10 candidate SNPs in seven genes identified in stage 1, one (rs744154) on intron 1 of ERCC4, a gene belonging to the nucleotide excision repair pathway, was associated with recessive protection from breast cancer after adjustment for multiple testing in stage 2 (odds ratio, 0.57; Bonferroni-adjusted P = 0.04). After considering potential functional SNPs in the region of high linkage disequilibrium that extends across the entire gene and upstream into the promoter region, we concluded that rs744154 itself could be causal. Although intronic, it is located on the first intron, in a region that is highly conserved across species, and could therefore be functionally important. This study suggests that common intronic variation in ERCC4 is associated with protection from breast cancer.

Association of sulfonylurea receptor 1 genotype with therapeutic response to gliclazide in type 2 diabetes

To investigate the effects of sulfonylurea receptor 1 (SUR1) exon 33 (TCC-->GCC, S1369A) polymorphism on responsiveness to gliclazide. About 115 patients with type 2 diabetes were treated with gliclazide for 8 weeks. SUR1 genotypes were tested by Taqman-PCR. After gliclazide treatment, there was association between T/G polymorphism and decrease of HbA1c. G carriers were more sensitive to gliclazide and the decrease of HbA1c was more significant than TT genotype (TT, 0.76%+/-1.70%; TG+GG, 1.60%+/-1.39%, P=0.044). The polymorphism of SUR1S1369A was associated with the therapeutic efficacy of gliclazide.

Candidate gene association study of type 2 diabetes in a nested case-control study of the EPIC-Potsdam cohort - role of fat assimilation

To search for common variants etiological for type 2 diabetes, we screened 15 genes involved in fat assimilation for sequence variants. Approximately 55 kb in promoter and coding regions, and intron/splice sites were sequenced by cycle sequencing. In the set of 15 genes, 71 single nucleotide polymorphisms (SNPs) were detected. 33 SNPs were presumed to be functionally significant and were genotyped in 192 incident type 2 diabetes subjects and 384 matched controls from the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort. A total of 27 SNPs out of 15 genes showed no statistical association with type 2 diabetes in our study. Six SNPs demonstrated nominal association with type 2 diabetes, with the most significant marker (FABP6 Thr79Met) having an adjusted odds ratio of 0.45 (95% CI 0.22-0.92) in homozygous Met allele carriers. Evidence for an association with disease status was also found for a novel Arg109Cys (g.2129C > T) variant of colipase, 5'UTR (rs2084202) and Met71Val (rs8192506) variants of diazepam-binding inhibitor, Arg298His (rs13283456) of PTGES2, and a novel promoter variant (g.-1324G > A) of SLC27A5. The results presented here provide preliminary evidence for the association of common variants in genes involved in fat assimilation with the genetic susceptibility of type 2 diabetes. However, they definitely need further verification.

Screening of 134 single nucleotide polymorphisms (SNPs) previously associated with type 2 diabetes replicates association with 12 SNPs in nine genes

More than 120 published reports have described associations between single nucleotide polymorphisms (SNPs) and type 2 diabetes. However, multiple studies of the same variant have often been discordant. From a literature search, we identified previously reported type 2 diabetes-associated SNPs. We initially genotyped 134 SNPs on 786 index case subjects from type 2 diabetes families and 617 control subjects with normal glucose tolerance from Finland and excluded from analysis 20 SNPs in strong linkage disequilibrium (r(2) > 0.8) with another typed SNP. Of the 114 SNPs examined, we followed up the 20 most significant SNPs (P < 0.10) on an additional 384 case subjects and 366 control subjects from a population-based study in Finland. In the combined data, we replicated association (P < 0.05) for 12 SNPs: PPARG Pro12Ala and His447, KCNJ11 Glu23Lys and rs5210, TNF -857, SLC2A2 Ile110Thr, HNF1A/TCF1 rs2701175 and GE117881_360, PCK1 -232, NEUROD1 Thr45Ala, IL6 -598, and ENPP1 Lys121Gln. The replication of 12 SNPs of 114 tested was significantly greater than expected by chance under the null hypothesis of no association (P = 0.012). We observed that SNPs from genes that had three or more previous reports of association were significantly more likely to be replicated in our sample (P = 0.03), although we also replicated 4 of 58 SNPs from genes that had only one previous report of association.

Potential impact of advanced clinical information technology on cancer care in 2015

New clinical information technologies now sporadically available will soon be in routine clinical use, bringing many changes to all phases of the cancer care continuum. For example, new technologies such as: (1) The next generation Internet; (2) Real-time clinical decision support systems; (3) Off-line, population-based systems; (4) Large, integrated, individual patient-level phenotypic and genotypic databases with intelligent data mining capabilities; (5) Wireless, invasive and non-invasive physiologic monitoring devices; (6) Natural Language Processing (NLP) systems; and (7) Mathematical models of complex biological systems all have the potential to impact significantly the provision of cancer care throughout its continuum. While new information management and communication techniques and technologies will reduce many of the inefficiencies and inaccuracies of our present systems, there will be an equal, and potentially far more dangerous, set of unintended consequences. Informatics investigators, cancer specialists, and health system administrators must focus on the study of what is working and what is not, as well as, on development and testing of the new clinical information management and communication technologies, if we are to be ready for the future.

Functional polymorphisms of HSPA5: possible association with bipolar disorder

Altered endoplasmic reticulum stress (ER) response signaling is suggested in bipolar disorder. Previously, we preliminarily reported the genetic association of HSPA5 (GRP78/BiP) with bipolar disorder. Here, we extended our analysis by increasing the number of Japanese case-control samples and NIMH Genetics Initiative bipolar trio samples (NIMH trios), and also analyzed schizophrenia samples. In Japanese, nominally significant association of one haplotype was observed in extended samples of bipolar disorder but not in schizophrenia. In NIMH trios, no association was found in total samples. However, an exploratory analysis suggested that the other haplotype was significantly over-transmitted to probands only from the paternal side. The associated haplotype in Japanese or NIMH pedigrees shared three common polymorphisms in the promotor, which was found to alter promotor activity. These findings suggested promotor polymorphisms of HSPA5 may affect the interindividual variability of ER stress response and may confer a genetic risk factor for bipolar disorder.

Large-scale search of single nucleotide polymorphisms for hepatocellular carcinoma susceptibility genes in patients with hepatitis C

Hepatitis C virus (HCV) infection is a major risk factor for developing hepatocellular carcinoma (HCC). The host genetic factors that are involved in the development of HCC in patients with HCV infection remain to be investigated. To search for single nucleotide polymorphisms (SNPs) in HCC susceptibility genes, 393 SNPs in 171 candidate genes were examined in 188 Japanese patients with chronic HCV infection, including 77 patients with HCC. HCC-related SNPs were then examined in another 188 patients (including 93 patients with HCC) with chronic HCV infection. Haplotype analyses of HCC-related genes were performed in a total of 376 patients. Of the 393 SNPs, 31 SNPs in 29 genes were significantly associated with HCC based on an initial screening (P < .05). Of these 31 SNPs, 3 SNPs of 3 genes (SCYB14, GFRA1, and CRHR2) were significantly associated with HCC in a secondary screening. Haplotype analyses of these 3 genes identified 2 haplotype blocks associated with HCC. In conclusion, these SNPs and haplotypes located in the SCBY14, CRHR2, and GFRA1 genes will be used as markers to identify a subgroup of Japanese patients with chronic HCV infection who are at high risk of developing HCC.

Genes and Type 2 Diabetes Mellitus

Type 2 diabetes (T2DM) comprises a group of entities with different genetic causes. In most patients, T2DM results from alterations of various genes, each having a partial and additive effect. The inheritance pattern is thus complex, and environmental factors play an important role in favoring or delaying the expression of the disease. The identification of susceptibility genes and genetic variants requires different methodological approaches. Here we address some of the most important strategies and findings on the genomic basis of T2DM, as well as evidence of genetic heterogeneity among populations. The identification of the underlying genetic causes of T2DM and other related traits such as obesity and hypertension will lead to the development of new therapeutic targets likely to impact the way we treat these diseases. Survival and quality of life for T2DM patients is expected to eventually increase, significantly lessening the socioeconomic burden of the disease.

Association of the ABCA1 gene polymorphisms with type 2 DM in a Japanese population

To examine the association of the ATP-binding cassette transporter 1 (ABCA1) gene with type 2 diabetes (DM), we studied genetic polymorphisms of the ABCA1 gene including its linkage disequilibrium (LD) and haplotype analyses using a Japanese population. A sample set (DM:72, IGT:75, and NGT:227) was genotyped with 34 SNPs distributed from the promoter region to the last exon of the ABCA1 gene. LD between SNPs was assessed in pairwise manner. Among 13 LD blocks constructed, an LD block at the 5'-region showed a significant difference in the haplotype distribution between the study groups (NGT vs. IGT + DM: overall p = 0.0180; NGT vs. DM: 0.0001). Fisher's exact probability test (NGT vs. DM) showed a significant association of the haplotype 2 of the LD block (p = 0.0001), with an odds ratio (OR) of 2.53 (95%CI:1.62-4.12). Diplotype analysis also showed a significant association of the diplotypes with the haplotype 2 (OR:2.59, 95%CI:1.48-4.54, p = 0.0013).

Effect of SNPs in protein kinase Cz gene on gene expression in the reporter gene detection system

AIM: To investigated the effects of the SNPs (rs411021, rs436045, rs427811, rs385039 and rs809912) on gene expression and further identify the susceptibility genes of type 2 diabetes.

METHODS: Ten allele fragments (49 bp each) were synthesized according to the 5 SNPs mentioned above. These fragments were cloned into luciferase reporter gene vector and then transfected into HepG2 cells. The activity of the luciferase was assayed. Effects of the SNPs on RNA splicing were analyzed by bioinformatics.

RESULTS: rs427811T allele and rs809912G allele enhanced the activity of the reporter gene expression. None of the 5 SNPs affected RNA splicing.

CONCLUSION: SNPs in protein kinase Cz (PKCZ) gene probably play a role in the susceptibility to type 2 diabetes by affecting the expression level of the relevant genes.

Association between chromogranin b gene polymorphisms and schizophrenia in the Japanese population

BACKGROUND

We found in previous work a significant association between schizophrenia and D20S95 on chromosome 20p12.3. In this study, we analyzed 10 microsatellite markers and found an association of schizophrenia with D20S882 and D20S905 that flank D20S95. The chromogranin B gene (CHGB) is 30 kb from D20S905. The chromogranin B (secretogranin I) belongs to a series of acidic secretory proteins that are widely expressed in endocrine and neuronal cells, and its cerebrospinal fluid levels have been reported to decrease in patients with chronic schizophrenia.

METHODS

We screened for polymorphisms in CHGB with polymerase chain reaction direct sequencing methods in 24 Japanese schizophrenic patients and identified a total of 22 polymorphisms. Allelic and genotypic distributions of detected polymorphisms were compared between unrelated Japanese schizophrenic patients (n = 192) and healthy control subjects (n = 192).

RESULTS

Statistically significant differences in the allelic distributions were found between schizophrenic patients and control subjects for 1058C/G (A353G) (corrected p = 7.7 x 10(-5)) and 1104A/G (E368E) (corrected p = 8.1 x 10(-6)). The 1058C/G and 1104A/G alleles were in almost complete linkage disequilibrium and were in linkage disequilibrium with D20S95.

CONCLUSIONS

Results suggest that the CHGB variations are involved in the susceptibility to schizophrenia in our study population.