Polymorphism In Regulatory Region Research Articles

IMAGING

Introduction: In mice, disruption of 5‐HTT function via knockout of the 5‐HTT gene reduces 5‐HT1A receptor density. In humans, the short allele (S) of the serotonin transporter (5‐HTTLPR) gene has been associated with decreased transcriptional activity and reduced 5‐HTT function. Furthermore, a promoter polymorphism in the 5‐HT1A receptor gene (–1018 C>G) inhibits the repression of transcription, which may lead to increased 5‐HT1A autoreceptor expression. We therefore investigated the effects of polymorphisms of the 5‐HTTLPR and 5‐HT1A receptor (–1018 C>G) genes on 5‐HT1A receptor density in humans using PET and [11C] WAY 100635 (a specific ligand for 5‐HT1A receptors). Methods: Thirty‐five healthy volunteers [27 males, mean (SD) age: 46 (13) years], who had previously undergone PET scans with [11C] WAY 100635, underwent blood collection for genotyping (i) the 5‐HT1A receptor gene single nucleotide polymorphism at the site ‐1018 C>G, (ii) the common 44 bp insertion/deletion polymorphism (∼ 1 kb from initiation site) in the upstream regulatory region of 5‐HTTLPR. PET scans were undertaken using the ECAT 953 and 966 scanners. Binding potential (BP) values were obtained using a simplified reference tissue model with a standard PET template. We carried out multivariate repeated measures ANOVA with 21 regions of interest as within‐subject factors and genetic polymorphisms, scanner, and gender as between‐subject factors. Results: Genotype frequencies of all the polymorphisms conformed to the Hardy‐Weinberg equilibrium. The “S” allele of 5‐HTTLPR gene showed significantly lower 11C WAY 100635 BP values when compared to the “L” allele (F = 4.8, df 1.27, P= .037) and this was independent of the scanner and gender effects. The 5‐HT1A receptor gene (–1018 c>g) did not show any significant genetic (allelic or genotypic) effects on 11C WAY 100635 BP values (F = .002, df 1.28, P= .9). Conclusions: This study demonstrates for the first time that a genetic polymorphism of the 5‐HT transporter gene indirectly affects 5‐HT1A receptor density in vivo. This may be mediated by a persistently increased 5‐HT tone associated with the “S” allele of 5‐HTTLPR causing a downregulation of 5‐HT1A receptors. Comment: This PET imaging study, so far available only in abstract form, was done in a group of volunteers and elegantly demonstrates how genetic polymorphism of the 5‐HT transporter gene can modify central 5‐HT1A activity. This is potentially important in migraine and depression, where serotonin levels may be reduced. Could this be another gene locus that may have relevance to migraineurs?—David S. Millson

UDP Glucuronosyltransferase (UGT) 1A6 Pharmacogenetics: I. Identification of Polymorphisms in the 5′-Regulatory and Exon 1 Regions, and Association with Human Liver UGT1A6 Gene Expression and Glucuronidation

UDP glucuronosyltransferase (UGT) 1A6 is a major isoform in human liver that glucuronidates numerous drugs, toxins, and endogenous substrates with high interindividual variability. The molecular basis for this variability remains unknown, although it likely involves genetic and environmental factors. Phenotype-genotype studies were conducted using a well characterized human liver bank (n = 54) and serotonin glucuronidation as a UGT1A6-specific phenotype marker. A positive moderate-to-heavy alcohol use history (>14 drinks per week) was the only demographic factor examined that correlated with phenotype and was associated with 2-fold higher serotonin glucuronidation (p < 0.001), UGT1A6 protein content (p = 0.004), and UGT1A6 mRNA content (p = 0.025). UGT1A6 gene resequencing identified three nonsynonymous polymorphisms (S7A, T181A, and R184S) in exon 1 and eight novel polymorphisms in the 5'-regulatory region (to -2052 base pairs). S7A was in complete linkage disequilibrium with three 5'-regulatory region polymorphisms (-1710c-->g, -1310del5, and -652g-->a). Initial univariate analyses did not identify any significant phenotype-genotype associations. However, in livers without substantial alcohol exposure, 50% lower UGT1A6 mRNA levels (p = 0.026) were found in carriers of the linked S7A-enhancer polymorphisms compared with noncarriers but without significant effect on UGT1A6 protein content or glucuronidation activities. Three major haplotypes, including (*)1A (reference), (*)1B (-1535g-->a and -427g-->c), and (*)2 (-1710c-->g, -1310del5, -652g-->a, S7A, T181A, and R184S), were identified, accounting for 90% of alleles. No association of haplotype with any of the phenotype measures could be discerned. In conclusion, although the identified UGT1A6 polymorphisms did not explain the observed glucuronidation variability, there does seem to be a significant role for environmental factors associated with alcohol consumption.

The -2518 Promotor Polymorphism in the MCP-1 Gene Is Associated with Systemic Sclerosis

Factors influencing the initiation or progression of sclerosis in patients with systemic sclerosis (SSc) are poorly understood. Monocyte chemotactic protein-1 (MCP-1) is a potent chemokine, which is upregulated in fibroblasts during development of sclerosis. In this study, we investigated the frequency of the functional -2518G MCP-1 promoter polymorphism in 18 patients with SSc and 139 healthy controls. In the lesional skin of the same SSc patients, expression of MCP-1 protein was examined by immunohistochemistry. To investigate a genotype/phenotype correlation, basal as well as tumor necrosis factor (TNF)-induced MCP-1 expression was analyzed in fibroblasts isolated from the skin of SSc patients with different MCP-1 genotypes by quantitative RT-PCR and ELISA. Genotyping for the -2518 (A/G) MCP-1 promotor polymorphism showed that GG homozygotes were significantly more frequent in patients with SSc than in controls (28%vs 6%). Results of immunohistochemistry revealed that MCP-1 was expressed in keratinocytes, infiltrating inflammatory cells, fibroblasts, and endothelial cells in scleroderma skin, whereas normal control skin showed no MCP-1 expression. MCP-1 expression in fibroblasts from GG-homozygote individuals tended to be stronger as compared to AG or AA genotypes. Furthermore, basal as well as TNF-induced MCP-1 expression of fibroblasts isolated from a GG-homozygote SSc patient was significantly higher than MCP-1 expression of fibroblasts isolated from heterozygote or AA-homozygote donors. The A -2518G polymorphism of the MCP-1 gene appears to affect MCP-1 expression of skin fibroblasts of patients with SSc. In accordance, the G/G genotype may predispose patients to SSc.

Functional Characterization of Amyloid β Precursor Protein Regulatory Elements: Rationale for the Identification of Genetic Polymorphism

Alzheimer's disease (AD) is characterized by the formation of senile plaques of the amyloid peptide (Abeta) derived from a large Abeta precursor protein (APP). Autosomally inherited or "familial" AD has only been previously demonstrated in connection with coding sequence missense mutations. Abnormal regulation of APP gene expression has been demonstrated to play a role in AD. Genome screen and linkage analysis suggest that the APP locus may predispose to AD. The aim is to characterize genetic variability in the APP gene within its upstream regulatory region and to determine whether that variability is associated with AD and affects the expression of APP. This article describes the rationale and strategy for identifying genetic polymorphisms in the APP regulatory region, including its promoter, to associate any variability with the disease.

The −1997 G/T Polymorphism in the COLIA1 Upstream Regulatory Region is Associated with Hip Bone Mineral Density (BMD) in Chinese Nuclear Families

Type I collagen is the most abundant protein of bone matrix, and the collagen type I alpha 1(COLIA1) gene has been considered one of the most important candidate genes for osteoporosis. In this study, we simultaneously tested linkage and/or association of the -1997 G/T polymorphism in the COLIA1 upstream regulatory region with the variation of bone mineral density (BMD) in 1263 subjects from 402 Chinese nuclear families, consisted of both parents and at least one healthy female offspring from 20 to 45 years of age. All the subjects were genotyped by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). BMD of the lumbar spine (L1-L4) and hip (respective and combined phenotype of the femoral neck, trochanter, and intertrochanter) was measured by dual-energy X-ray absorptiometry (DXA). By using the tests implemented in program QTDT (quantitative transmission disequilibrium test), we found significant within-family association (via TDT) between the -1997 G/T polymorphism with BMD variation at all the hip sites (respective and combined phenotypes, P < 0.05). The amount of BMD variation explained by the -1997G/T polymorphism was 1.6%, 2.0%, 1.2%, and 1.3% at the total hip, femoral neck, trochanter, and intertrochanter, respectively. Because of the limited number of sib pairs in this sample, we did not find evidence of linkage. In summary, the -1997 G/T polymorphism in the COLIA1 gene is likely to be in linkage disequilibrium with a nearby functional polymorphism affecting hip BMD, or the -1997 G/T polymorphism itself may have an important effect on the variation of hip BMD in our Chinese sample.

Comprehensive association analysis of APOE regulatory region polymorphisms in Alzheimer disease.

Several recent case-control studies have examined the association between single nucleotide polymorphisms (SNPs) in the promoter region of the apolipoprotein E gene (APOE) and risk of Alzheimer disease (AD), with conflicting results. We assessed the relation between five APOE region SNPs and risk of AD in both case-control and family-based analyses. We observed a statistically significant association with the +5361T allele in the overall case-control analysis (P value=0.04) after adjusting for the known effect of the APOE-4 allele. Further analysis revealed this association to be limited to carriers of the APOE-4 allele. Age-stratified analyses in the patients with age at onset of 80 years or greater and age-matched controls showed that the -219T allele (P value=0.009) and the +113C allele (P value=0.03) are associated with increased risk of AD. Despite these findings, haplotype and family-based association analyses were unable to provide evidence that the APOE region SNPs influenced risk of AD independent of the APOE-4 allele. In addition to risk, we tested for association between the SNPs and age at onset of AD, but found no association in the case-control or family based analyses. In conclusion, SNPs +5361, or a SNP in strong linkage disequilibrium, may confer some additional risk for developing AD beyond the risk due to APOE-4; however, the effect independent of APOE-4 is likely to be small.

Association between the A-2518G polymorphism in the monocyte chemoattractant protein-1 gene and insulin resistance and Type 2 diabetes mellitus.

The molecular mechanisms of obesity-related insulin resistance are incompletely understood. Macrophages accumulate in adipose tissue of obese individuals. In obesity, monocyte chemoattractant protein-1 (MCP-1), a key chemokine in the process of macrophage accumulation, is overexpressed in adipose tissue. MCP-1 is an insulin-responsive gene that continues to respond to exogenous insulin in insulin-resistant adipocytes and mice. MCP-1 decreases insulin-stimulated glucose uptake into adipocytes. The A-2518G polymorphism in the distal regulatory region of MCP-1 may regulate gene expression. The aim of this study was to investigate the impact of this gene polymorphism on insulin resistance. We genotyped the Ludwigshafen Risk and Cardiovascular Health (LURIC) cohort ( n=3307). Insulin resistance, estimated by homeostasis model assessment, and Type 2 diabetes were diagnosed in 803 and 635 patients respectively. Univariate analysis revealed that plasma MCP-1 levels were significantly and positively correlated with WHR ( p=0.011), insulin resistance ( p=0.0097) and diabetes ( p<0.0001). Presence of the MCP-1 G-2518 allele was associated with decreased plasma MCP-1 ( p=0.017), a decreased prevalence of insulin resistance (odds ratio [OR]=0.82, 95% CI: 0.70-0.97, p=0.021) and a decreased prevalence of diabetes (OR=0.80, 95% CI: 0.67-0.96, p=0.014). In multivariate analysis, the G allele retained statistical significance as a negative predictor of insulin resistance (OR=0.78, 95% CI: 0.65-0.93, p=0.0060) and diabetes (OR=0.80, 95% CI: 0.66-0.96, p=0.018). In a large cohort of Caucasians, the MCP-1 G-2518 gene variant was significantly and negatively correlated with plasma MCP-1 levels and the prevalence of insulin resistance and Type 2 diabetes. These results add to recent evidence supporting a role for MCP-1 in pathologies associated with hyperinsulinaemia.

Pharmacogenetics of selective serotonin reuptake inhibitor response: a 6-month follow-up.

We previously reported the association between some genetic factors and short-term antidepressant outcome. In the present paper we investigated the same gene variants in a prospective 6-months naturalistic follow-up. The sample included 185 inpatients affected by recurrent major depression consecutively admitted to the Psychiatric Inpatient Unit of San Raffaele Hospital from 1998 to 2003 and prospectively followed for 6 months after their recovery. All the patients were undertaking continuation therapy. The functional polymorphism in the upstream regulatory region of the serotonin transporter gene (SERTPR), the tryptophan hydroxylase A218C substitution, a VNTR polymorphism located 1.2 kb upstream of the monoamine oxidase-A coding sequences, the CLOCK gene T3111C and the PER3exon15 gene T1940G substitutions were analysed, using PCR-based techniques. No association was found between clinical variables and relapses; subjects showing TT genotype at CLOCK gene tended to relapse within 6 months after recovery more than TC and CC subjects taken together. A non-significant tendency of SERTPR*s/s subjects to a minor frequency of relapse was also observed. Some subjects showing remission after acute treatment relapsed within 6 months, despite undertaking a maintenance treatment; the causes could be heterogeneous, but CLOCK gene variants may influence the outcome.

Polymorphism in the bovine BOLA-DRB3 upstream regulatory regions detected through PCR-SSCP and DNA sequencing

In the present work, we describe through polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing the polymorphism within the URR-BoLA-DRB3 in 15 cattle breeds. In total, seven PCR-SSCP defined alleles were detected. The alignment of studied sequences showed six polymorphic sites (four transitions, one transversion and one deletion) in the interconsensus regions of the BoLA-DRB3 upstream regulatory region (URR), while the consensus boxes were invariant. Five out of six detected polymorphic sites were of one nucleotide substitution in the interconsensus regions. It is expected that these mutations do not affect significantly the level of expression. In contrast, the deletion observed in the sequence AY364455 between CCAAT and TATA boxes could have some effect on affinity interactions between the promoter region and the transcription factors. The URR-BoLA-DRB3 DNA analyzed sequences showed moderate level of nucleotide diversity, high level of identity among them and were grouped in the same clade in the phylogenetic tree. In addition, the phylogenetic tree, the similarity analysis and the sequence structure confirmed that the fragment analyzed in this study corresponds to the URR-BoLA-DRB3. The functional role of the observed polymorphic sites among the regulatory motifs in bovine needs to be analyzed and confirmed by means of gene expression assays.

SNP Discovery in Pooled Samples With Mismatch Repair Detection

A targeted discovery effort is required to identify low frequency single nucleotide polymorphisms (SNPs) in human coding and regulatory regions. We here describe combining mismatch repair detection (MRD) with dideoxy terminator sequencing to detect SNPs in pooled DNA samples. MRD enriches for variant alleles in the pooled sample, and sequencing determines the nature of the variants. By using a genomic DNA pool as a template, approximately 100 fragments were amplified and subsequently combined and subjected en masse to the MRD procedure. The variant-enriched pool from this one MRD reaction is enriched for the population variants of all the tested fragments. Each fragment was amplified from the variant-enriched pool and sequenced, allowing the discovery of alleles with frequencies as low as 1% in the initial population. Our results support that MRD-based SNP discovery can be used for large-scale discovery of SNPs at low frequencies in a population.

Lack of relationship between CO2 reactivity and serotonin transporter gene regulatory region polymorphism in panic disorder.

Changes in the function of the serotonergic system influence both panic phobic symptoms and carbon dioxide (CO2) reactivity in patients with panic disorder. Schmidt et al. [2000: J Abnorm Psychol 109(2):308-320] recently reported a predictive role of the genetic variants of the 5-HTTLPR on the fearful response to CO2 in healthy controls. We tested the hypothesis that the heterogeneity of CO2 reactivity in patients with panic disorder could be related to the allelic variation of the 5-HTT promoter. Ninety-five patients with panic disorder were challenged with 35% CO2. 5-HTTLPR allelic variation in each subject was determined using a PCR-based method. There were no differences for all the measures of CO2 reactivity among the genotype groups. CO2 reactivity of patients with panic disorder seems not to be influenced by the genetic variants of the 5-HTTLPR; this finding does not support a role for the serotonin transporter in the etiopathogenesis of CO2 reactivity in panic disorder.

Further evidence for a possible association between serotonin transporter gene and lithium prophylaxis in mood disorders.

We previously reported an association between the functional polymorphism in the upstream regulatory region of the serotonin transporter gene (SERTPR) and the prophylactic efficacy of lithium in a sample of 201 Italian subjects affected by Mood disorders. The aim of the present study was to replicate analyses on an independent sample. In total, 83 subjects affected by Bipolar disorder were recruited in the Mood Disorders Clinic of the Eginition Hospital of the Athens University, Medical School Department of Psychiatry. All patients were administered with lithium as prophylactic therapy and they were prospectively observed for at least 3 years. Subjects were typed for their SERTPR variant using polymerase chain reaction techniques. SERTPR variants were associated with lithium outcome among those subjects who had few manic episodes before lithium treatment and, as a trend, among subjects who received a high daily dose of lithium (> or =1200 mg/die). In both cases, subjects with the l/l variant showed a higher probability to develop an illness episode within 3 years of prophylactic treatment with lithium. The present study confirmed our previous observation of a better response of SERTPR*l/s carriers, but could not confirm a poor efficacy in subjects with the SERTPR*s/s genotype. Notwithstanding the conflicting results, SERTPR variants are a possible liability factor for lithium long-term efficacy in mood disorders. Further studies on independent and large samples are required to determine the reliability and direction of the possible association between SERTPR variants and lithium outcome.

Serotonin transporter regulatory region polymorphism is associated with anorexia nervosa.

Several lines of evidence support possible serotonin transporter (5-HTT) involvement in modulating eating disorders (ED). The 5-HTT gene is a good candidate for genetic studies on the course of ED, despite controversy concerning the association between polymorphism in the 5-HTT gene promoter region (5-HTTLPR) and ED. Comparison of 5-HTTLPR distribution in 195 female Japanese ED patients and 290 age- and gender-matched control subjects facilitated examining the association between the course of the disease and 5-HTTLPR in 138 of 195 ED subjects. The 5-HTTLPR S allele frequency was significantly higher in subjects with anorexia nervosa (AN) than in control subjects. Among subjects observed > or =3 years, the S allele frequency was significantly higher in those diagnosed as AN at ED onset than in those diagnosed as AN in this study. The 5-HTTLPR S allele might play some role in the development of AN with persistent disease.

MCP-1 gene regulatory region polymorphism in Chinese children with mild, moderate and near-fatal asthma.

A polymorphism in the monocyte chemoattractant protein 1 (MCP-1) gene regulatory region has been associated with asthma in Caucasians. This polymorphism is possibly endemic to the Asian region, but its impact on Asian populations is unclear. In addition, the relationship of this marker with life-threatening asthma has not been clarified. The aim of this study was to test the genetic association between the MCP-1 -2518A/G polymorphism and asthma/atopy in a cohort of Chinese children, with particular emphasis on those patients who had experienced life-threatening asthma attacks. Forty-eight children with near-fatal asthma, 134 mild-to-moderate asthmatics, 69 allergic-disorder cases without asthma, and 107 nonasthmatic, nonatopic control children were genotyped by a polymerase chain reaction-based assay. Comparison of the four groups of children (n = 358) revealed no detectable differences in genotype or allele frequencies of the MCP-1 -2518A/G polymorphism. There was no evidence of association between the polymorphism and any of the outcomes of interest including clinical severity, blood eosinophil count, atopy, total serum IgE levels, and degree of bronchial hyper-responsiveness. These results suggest that the MCP-1 -2518A/G polymorphism is not a risk factor for near-fatal asthma. Furthermore, this polymorphism seems to play no role in the development of asthma or atopy in Chinese subjects, possibly as a result of the genetic heterogeneity between Asian and Caucasian populations with respect to regulation of MCP-1 expression. Our results underscore the necessity of accounting for ethnic background in the investigation of asthma-predisposition genes.

From molecular biology to pharmacogenetics: a review of the literature on antidepressant treatment and suggestions of possible candidate genes.

Pharmacogenetic studies in mood disorders are raising increasing interest, after the first findings of a significant association between antidepressant response and a functional polymorphism in the upstream regulatory region of the serotonin transporter gene (SERTPR). However, the results of published studies are not unequivocal. The reasons of these discordances could be various: the small samples, which could affect the power to detect a good effect size, the use of different and often not comparable scales and methodologies to assess the response rates. Notwithstanding all these limitations, the choice of candidate genes involved in antidepressant response is one of the crucial steps to target future research. In the present paper, we reviewed the literature concerning pharmacogenetic studies on antidepressant response. This analysis evidenced a number of studies consistently confirming the association of the SERTPR short variant with a poorer response to antidepressants, at least for the Caucasian samples. Further unreplicated positive findings included tryptophan hydroxylase (TPH), G-protein beta(3)-subunit (Gbeta(3)) and serotonin receptor 2A gene polymorphisms. Through the review, we also suggested possible candidate genes for future studies, which are involved in the main monoaminergic neurotransmitters pathways (norepinephrine, dopamine, serotonin), in substance P, neurokinines and glutamate systems, in the intracellular signal transduction pathway, in the phosphorylation process and in the control of the transcriptional activity system.

Determination of Paraoxonase 1 Status and Genotypes at Specific Polymorphic Sites

The procedures for determining paraoxonase (PON1) status and for determining PON1 genotypes for polymorphisms in coding and important regulatory regions are described. PON1 status is determined by a functional two-substrate analysis of plasma PON1 activities. Differences in catalytic efficiency of the PON1₁₉₂Q and PON1₁₉₂R alloforms result in the clear separation of all three phenotypes at position 192 (Q/Q, Q/R, R/R) and at the same time, the two-substrate analysis indicates activity levels of PON1. Because the enzyme activity levels are as important as the polymorphic genotypes, this two-substrate analysis of PON1 status provides the most relevant information for investigating the association of PON1 genetics with susceptibilities to disease, organophosphorus insecticide sensitivity, and pharmacokinetic status of drug metabolism. Genotyping of polymorphic sites alone fails to provide this important information but can be useful for gene frequency determination and forensic analysis. Analytical procedures for determining PON1 status and genotypes are described.

MCP-1 gene regulatory region polymorphism in Chinese children with mild, moderate and near-fatal asthma

Rationale A polymorphism in the MCP-1 gene regulatory region has been associated with asthma in the Caucasians. This polymorphism is possibly endemic to the Asian region, but its impact on Asian populations is unclear. In addition, the relationship of this marker with life-threatening asthma has not been clarified. The aim of this study was to test the genetic association between the MCP-1 −2518A/G polymorphism and asthma/atopy in a cohort of Chinese children, with particular emphasis on those patients who had experienced life-threatening asthma attacks. Methods Forty-eight children with near-fatal asthma, 134 mild-to-moderate asthmatics, 69 allergic-disorder cases without asthma; and 107 nonasthmatic nonatopic control children were genotyped by a PCR-based assay. Results Comparison of the 4 groups of children (n=358) revealed no detectable differences in genotypes or allele frequencies of the MCP-1 −2518A/G polymorphism. There was no evidence of association between the polymorphism and any of the outcomes of interest including clinical severity, blood eosinophil count, atopy, total serum IgE levels, and degree of bronchial hyperresponsiveness. Conclusions These results suggest that the MCP-1 −2518A/G polymorphism is not a risk factor for near-fatal asthma. Furthermore, this polymorphism seems to play no role in the development of asthma or atopy in Chinese subjects, possibly as a result of the genetic heterogeneity between Asian and Caucasian populations with respect to regulation of MCP-1 expression. Our results underscore the necessity of accounting for ethnic background in the investigation of asthma-predisposition genes.

Functional genetic polymorphisms in cytokines and metabolic genes as additional genetic markers for susceptibility to develop type 1 diabetes.

Genetic association with type 1 diabetes (T1D) has been established for two chromosomal regions: HLA DQ/DR (IDDM1) and INS VNTR (IDDM2). To identify additional genetic markers, we tested polymorphisms in regulatory regions of several cytokine and important metabolic genes. These polymorphisms exhibit functional consequences for expression and function. Functional genetic polymorphisms of proinflammatory (T-helper-1: IL-2, IL-12 and IFN-gamma), anti-inflammatory (T-helper-2: IL-4, IL-6 and IL-10) and metabolic (IGF-I, VDR and INS) genes were determined in 206 Dutch simplex families with juvenile onset T1D and the results were analysed using the transmission disequilibrium test. Significantly increased transmission to T1D probands was observed for the loci IDDM1, IDDM2 and the vitamin D receptor. Although none of the other individual polymorphisms was associated with disease individually, the combination of T-helper-2 and metabolic/growth alleles IL-10(*)R2, IL-4(*)C, VDR(*)C and IGF-I(*)wt was found to be transmitted more frequently than expected (67%, P(c)=0.015). We conclude that additional genetic predisposition to T1D is defined by combinations of markers (eg Th2 and metabolic) rather than by a single marker. The consequences of the increased transmission of a low Th2 expressing genotypes together with a normal Th1 profile may result in a net proinflammatory cytokine expression pattern.

IL-10 haplotypes as possible predictors of spontaneous clearance of HCV infection.

In hepatitis C virus infection an inappropriate ratio of pro-inflammatory and anti-inflammatory cytokines may either determine different outcomes of the infection or affect the benefit of antiviral treatment. Given that polymorphisms in regulatory regions of cytokine genes influence cytokine production, we determined frequency of polymorphisms of IL-10, IFNgamma, and TNFalpha genes in HCV-infected patients and healthy controls, and investigated their association with either ongoing or cleared HCV infection, or with response to treatment. Genomic DNA from 270 patients and 145 controls sharing the same ethnic background was studied by polymerase chain reaction, restriction enzyme digestion, direct sequencing, and microsatellite analysis. The IL-10 ATA haplotype was more frequent in patients with spontaneous HCV RNA clearance (36.0%) than in patients with persistent infection (23%) (p=0.009, p corrected = 0.036). Neither TNF -308 and -238 polymorphisms nor IFNgamma alleles variability were associated with different HCV outcome. However, the combination of ATA homozygous state and IFNgamma 119 allele was more frequent in patients with spontaneous HCV clearance than in patients with ongoing disease (p=0.012; p corrected = 0.048). We could not confirm the reported effect of genetic influence on the response to treatment. Our findings indicate that heterogeneity in the promoter region of the IL-10 gene has a role in determining a spontaneous favourable outcome of HCV infection.

Despite the general correlation of the serotonin transporter gene regulatory region polymorphism ( 5-HTTLPR) and platelet serotonin concentration, lower platelet serotonin concentration in migraine patients is independent of the 5-HTTLPR variants

Platelet serotonin (5-HT) concentrations in a headache-free period during the mid-follicular phase and the serotonin transporter gene regulatory region polymorphism ( 5-HTTLPR) were measured in female migraine patients without aura ( n=64) and healthy controls ( n=42). High-pressure liquid chromatography (HPLC) was used to determine the platelet 5-HT concentration and genetic polymorphism was determined by polymerase chain reaction. Significantly lower platelet 5-HT concentrations were found in migraine patients compared to controls. Concerning the 5-HTTLPR polymorphism, the S/S genotype was associated with a significantly higher platelet 5-HT concentration ( P=0.027) in the whole study population. This association between the 5-HTTLPR genotypes and platelet 5-HT concentrations was independent of the diagnosis. In addition, the platelet 5-HT concentration was lower in migraineurs in all genotypes (S/S, S/L, L/L). In conclusion, 5-HTTLPR variants may have an effect on the platelet 5-HT concentrations, but the lower 5-HT concentrations in migraine patients seem to be determined by other factors.