Genome-wide association analysis of genetic generalized epilepsies implicates susceptibility loci at 1q43, 2p16.1, 2q22.3 and 17q21.32

Genetic generalized epilepsies (GGEs) have a lifetime prevalence of 0.3% and account for 20-30% of all epilepsies. Despite their high heritability of 80%, the genetic factors predisposing to GGEs remain elusive. To identify susceptibility variants shared across common GGE syndromes, we carried out a two-stage genome-wide association study (GWAS) including 3020 patients with GGEs and 3954 controls of European ancestry. To dissect out syndrome-related variants, we also explored two distinct GGE subgroups comprising 1434 patients with genetic absence epilepsies (GAEs) and 1134 patients with juvenile myoclonic epilepsy (JME). Joint Stage-1 and 2 analyses revealed genome-wide significant associations for GGEs at 2p16.1 (rs13026414, P(meta) = 2.5 × 10(-9), OR[T] = 0.81) and 17q21.32 (rs72823592, P(meta) = 9.3 × 10(-9), OR[A] = 0.77). The search for syndrome-related susceptibility alleles identified significant associations for GAEs at 2q22.3 (rs10496964, P(meta) = 9.1 × 10(-9), OR[T] = 0.68) and at 1q43 for JME (rs12059546, P(meta) = 4.1 × 10(-8), OR[G] = 1.42). Suggestive evidence for an association with GGEs was found in the region 2q24.3 (rs11890028, P(meta) = 4.0 × 10(-6)) nearby the SCN1A gene, which is currently the gene with the largest number of known epilepsy-related mutations. The associated regions harbor high-ranking candidate genes: CHRM3 at 1q43, VRK2 at 2p16.1, ZEB2 at 2q22.3, SCN1A at 2q24.3 and PNPO at 17q21.32. Further replication efforts are necessary to elucidate whether these positional candidate genes contribute to the heritability of the common GGE syndromes.

Association between genetic variation in a region on chromosome 11 and schizophrenia in large samples from Europe

Recent molecular studies have implicated common alleles of small to moderate effect and rare alleles with larger effect sizes in the genetic architecture of schizophrenia (SCZ). It is expected that the reliable detection of risk variants with very small effect sizes can only be achieved through the recruitment of very large samples of patients and controls (that is tens of thousands), or large, potentially more homogeneous samples that have been recruited from confined geographical areas using identical diagnostic criteria. Applying the latter strategy, we performed a genome-wide association study (GWAS) of 1169 clinically well characterized and ethnically homogeneous SCZ patients from a confined area of Western Europe (464 from Germany, 705 from The Netherlands) and 3714 ethnically matched controls (1272 and 2442, respectively). In a subsequent follow-up study of our top GWAS results, we included an additional 2569 SCZ patients and 4088 controls (from Germany, The Netherlands and Denmark). Genetic variation in a region on chromosome 11 that contains the candidate genes AMBRA1, DGKZ, CHRM4 and MDK was significantly associated with SCZ in the combined sample (n=11 540; P=3.89 × 10(-9), odds ratio (OR)=1.25). This finding was replicated in 23 206 independent samples of European ancestry (P=0.0029, OR=1.11). In a subsequent imaging genetics study, healthy carriers of the risk allele exhibited altered activation in the cingulate cortex during a cognitive control task. The area of interest is a critical interface between emotion regulation and cognition that is structurally and functionally abnormal in SCZ and bipolar disorder.

Evaluating SKI as a candidate gene for non-syndromic cleft lip with or without cleft palate

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common of all congenital malformations and has a multifactorial etiology. Findings in mice suggest that the v-ski sarcoma viral oncogene homolog (SKI) gene is a candidate gene for orofacial clefting. In humans, a significant association between rs2843159 within SKI and NSCL/P has been reported in patients from the Philippines and South America. In the South American patients, the association was driven by the subgroup of patients with non-syndromic cleft lip only (NSCLO). Here we investigated the association with rs2843159 in a Mayan Mesoamerican population (172 NSCL/P patients and 366 controls). In addition, we analyzed the phenotypic subgroups NSCLO and non-syndromic cleft of lip and palate (NSCLP). A trend towards association between rs2843159 and NSCL/P was observed in the Mayan cohort (P = 0.097), and we found a stronger association in the NSCLP subgroup (P = 0.072) despite a limited sample size. To investigate whether other common variants within the SKI gene contribute to NSCL/P susceptibility in European and Asian populations, we also analyzed genotypic data from two recent genome-wide association studies using set-based statistical approaches. These analyses detected a trend toward association in the European population. Our data provide limited support for the hypothesis that common SKI variants are susceptibility factors for NSCL/P.

Genome-wide meta-analyses of nonsyndromic cleft lip with or without cleft palate identify six new risk loci

We have conducted the first meta-analyses for nonsyndromic cleft lip with or without cleft palate (NSCL/P) using data from the two largest genome-wide association studies published to date. We confirmed associations with all previously identified loci and identified six additional susceptibility regions (1p36, 2p21, 3p11.1, 8q21.3, 13q31.1 and 15q22). Analysis of phenotypic variability identified the first specific genetic risk factor for NSCLP (nonsyndromic cleft lip plus palate) (rs8001641; P(NSCLP) = 6.51 × 10(-11); homozygote relative risk = 2.41, 95% confidence interval (CI) 1.84-3.16).

High levels of brain-type creatine kinase activity in human platelets and leukocytes: a genetic anomaly with autosomal dominant inheritance

The ectopic expression in peripheral blood cells of the brain-type creatine kinase (CKB) is an autosomal dominant inherited anomaly named CKBE (MIM ID 123270). Here, we characterized the CK activity in serum, platelets (PLT) and leukocytes (WBC) of 22 probands (from 8 unrelated families) and 10 controls. CK activity was measured by standard UV-photometry. Expression of the CKB gene was analyzed by real-time PCR and Western blotting. DNA sequencing including bisulfite treatment was used for molecular analysis of the CKB gene. Serum CK levels were comparable between probands and controls. CKBE probands revealed significantly higher CK activity in PLT (3.7 ± 2.7 versus 179.2 ± 83.0 U/10(12) PLT; p<0.001) and WBC (0.4 ± 0.3 versus 2.6 ± 2.1 U/10(9) WBC; p=0.004). Inhibitory anti-CKM antibodies did not affect CK activity indicating that the CK activity is generated exclusively by the CK-BB isoenzyme. CKB mRNA and protein levels were significantly higher in PLT and WBC from probands compared to controls. Re-sequencing of the entire CKB gene and methylation analysis of a CpG island revealed no alteration in CKBE probands. The genetic basis of CKBE remains unclear, however, we propose that a de-methylated CKB gene is inherited that leads to high CKB expression levels in myeloic precursor cells in the bone marrow.

Geostatistical inference of main Y-STR-haplotype groups in Europe

We examined the multifarious genetic heterogeneity of Europe and neighboring regions from a geographical perspective. We created composite maps outlining the estimated geographical distribution of major groups of genetically similar individuals on the basis of forensic Y-chromosomal markers. We analyzed Y-chromosomal haplotypes composed of 7 highly polymorphic STR loci, genotyped for 33,010 samples, collected at 249 sites in Europe, Western Asia and North Africa, deposited in the YHRD database (www.yhrd.org). The data set comprised 4176 different haplotypes, which we grouped into 20 clusters. For each cluster, the frequency per site was calculated. All geostatistical analysis was performed with the geographic information system GRASS-GIS. We interpolated frequency values across the study area separately for each cluster. Juxtaposing all 20 interpolated surfaces, we point-wisely screened for the highest cluster frequencies and stored it in parallel with the respective cluster label. We combined these two types of data in a composite map. We repeated this procedure for the second highest frequencies in Europe. Major groups were assigned to Northern, Western and Eastern Europe. North Africa built a separate region, Southeastern Europe, Turkey and Near East were divided into several regions. The spatial distribution of the groups accounting for the second highest frequencies in Europe overlapped with the territories of the largest countries. The genetic structure presented in the composite maps fits major historical geopolitical regions and is in agreement with previous studies of genetic frequencies, validating our approach. Our genetic geostatistical approach provides, on the basis of two composite maps, detailed evidence of the geographical distribution and relative frequencies of the most predominant groups of the extant male European population, examined on the basis of forensic Y-STR haplotypes. The existence of considerable genetic differences among geographic subgroups in Europe has important consequences for the statistical inference in forensic Y-STR haplotype analyses.

SUMO1 as a candidate gene for non-syndromic cleft lip with or without cleft palate: no evidence for the involvement of common or rare variants in Central European patients

OBJECTIVE

Studies in mice and humans have suggested that SUMO1, which codes for the small ubiquitin-related modifier 1 (SUMO1), is a promising candidate gene for non-syndromic cleft lip with or without cleft palate (NSCL/P). To investigate the possible involvement of this gene in NSCL/P patients from Central Europe, we performed: (i) a case control association study, and (ii) a resequencing study.

METHODS

Genotyping and the subsequent single marker and haplotype association analyses were performed for 413 NSCL/P patients and 412 controls. A total of 17 tagging single-nucleotide polymorphisms (SNPs) were used. In the resequencing study, the complete coding region and splice sites were sequenced in 65 index patients from multiply affected families.

RESULTS

One of the 17 tested SNPs (rs16838917) had a borderline significant P-value of 0.0416 in the single-marker association analysis. However, this result did not withstand correction for multiple testing (P(corr)=0.707). No association was observed for any haplotypic marker combination. Sequencing failed to identify any novel rare sequence variants.

CONCLUSIONS

The results of the present study do not support the hypothesis that common or rare variants in SUMO1 play a significant role in the development of NSCL/P in Central-European patients. However, smaller effects of common variants or the presence of rare high penetrance mutations in other non-investigated familial cases cannot be excluded. Further analysis of SUMO1 in independent samples from Central European and other populations is therefore warranted.

Genome-wide association-, replication-, and neuroimaging study implicates HOMER1 in the etiology of major depression

BACKGROUND

Genome-wide association studies are a powerful tool for unravelling the genetic background of complex disorders such as major depression.

METHODS

We conducted a genome-wide association study of 604 patients with major depression and 1364 population based control subjects. The top hundred findings were followed up in a replication sample of 409 patients and 541 control subjects.

RESULTS

Two SNPs showed nominally significant association in both the genome-wide association study and the replication samples: 1) rs9943849 (p(combined) = 3.24E-6) located upstream of the carboxypeptidase M (CPM) gene and 2) rs7713917 (p(combined) = 1.48E-6), located in a putative regulatory region of HOMER1. Further evidence for HOMER1 was obtained through gene-wide analysis while conditioning on the genotypes of rs7713917 (p(combined) = 4.12E-3). Homer1 knockout mice display behavioral traits that are paradigmatic of depression, and transcriptional variants of Homer1 result in the dysregulation of cortical-limbic circuitry. This is consistent with the findings of our subsequent human imaging genetics study, which revealed that variation in single nucleotide polymorphism rs7713917 had a significant influence on prefrontal activity during executive cognition and anticipation of reward.

CONCLUSION

Our findings, combined with evidence from preclinical and animal studies, suggest that HOMER1 plays a role in the etiology of major depression and that the genetic variation affects depression via the dysregulation of cognitive and motivational processes.

Genes that determine immunology and inflammation modify the basic defect of impaired ion conductance in cystic fibrosis epithelia

Background

The cystic fibrosis (CF) basic defect, caused by dysfunction of the apical chloride channel CFTR in the gastrointestinal and respiratory tract epithelia, has not been employed so far to support the role of CF modifier genes.

Methods

Patients were selected from 101 families with a total of 171 F508del-CFTR homozygous CF patients to identify CF modifying genes. A candidate gene based association study of 52 genes on 16 different chromosomes with a total of 182 genetic markers was performed. Differences in haplotype and/or diplotype distribution between case and reference CF subpopulations were analysed.

Results

Variants at immunologically relevant genes were associated with the manifestation of the CF basic defect (0.01<Praw<0.0001 at IL1B, TLR9, TNFα, CD95, STAT3 and TNFR). The intragenic background of F508del-CFTR chromosomes determined disease severity and manifestation of the basic defect (Praw=0.0009). Allele distributions comparing transmitted and non-transmitted alleles were distorted at several loci unlinked to CFTR.

Conclusions

The inherited capabilities of the innate and adaptive immune system determine the manifestation of the CF basic defect. Variants on F508del-CFTR chromosomes contribute to the observed patient-to-patient variability among F508del-CFTR homozygotes. A survivor effect, manifesting as a transmission disequilibrium at many loci, is consistent with the improvement of clinical care over the last decades, resulting in a depletion of risk alleles at modifier genes. Awareness of non-genetic factors such as improvement of patient care over time is crucial for the interpretation of CF modifier studies.

Spatial assessment of Argentinean genetic admixture with geographical information systems

In recent years there has been much attention to Argentinean population stratification. We were interested in assessing population stratification from a geographical perspective and summarizing it in form of maps. We mapped the genetic admixture of the extant male population in central and northern Argentina on the basis of forensic Y-chromosomal haplotypes. We addressed the question which group of genetically similar individuals is predominant in this area. Haplotypes containing seven Y-chromosomal short tandem repeat polymorphisms (Y-STRs), also known as microsatellites - DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393 - were constructed for 145 individuals, recruited in 10 provinces. 97 distinct haplotypes were clustered into four clusters according to molecular distances. A genetic geostatistical analysis was conducted with the open-source geographical information system GRASS GIS. For each haplotype cluster, the according frequency was spatially interpolated over the total study area. Juxtaposing the interpolation surfaces, we screened point-wisely the maximal frequency as well as the label of the respective cluster. The screening results were combined in one summary map. We repeated this procedure for the second maximal frequencies. The resulting maps subdivide the study area into continuous regions comprising one predominant group of similar haplotypes. The first summary map divides the study area into three regions and the second summary map divides the area into four regions. The results of our analysis indicate that two groups of similar European haplotypes alternatively dominate the largest extension of the Argentinean territory. A third group, including South-American haplotypes, dominates the indigenous northwestern Argentinean area. The last group, including worldwide dispersed haplotypes, preponderates in frequency in second place in central Argentina. Our findings confirm a widespread European paternal ancestry, a substantial Amerindian contribution in the northwest, as well as a considerable proportion of diverse paternal lineages. In this work, we further discuss these findings in reference to ethno-historical, genetic, and demographic information.

Feasible and successful: genome-wide interaction analysis involving all 1.9 x 10(11) pair-wise interaction tests

The Genome-Wide Association Study (GWAS) is the study design of choice for detecting common genetic risk factors for multifactorial diseases. The performance of full Genome-Wide Interaction Analyses (GWIA) has always been considered computationally challenging. Two-stage strategies to reduce the amount of numerical analysis require the detection of single marker effects or prior pathophysiological hypotheses before the analysis of interaction. This prevents the detection of pure epistatic effects. Our case-control study in idiopathic generalized epilepsy demonstrates that a full GWIA is feasible through use of data compression, specific data representation, interleaved data organization, and parallelization of the analysis on a multi-processor system. Following extensive quality control of the genotypes, our final list of top interaction hits contains only pairs of interacting SNPs with negligible marginal effects. The TOP HIT interaction was between a SNP-pair intragenic to gene DNER (chr 2) and gene CTNNA3 (chr 10). Both of these genes are functionally involved in neuronal migration, synaptogenesis, and the formation of neuronal circuits. Our results therefore indicate a possible interaction between these two genes in epileptogenesis. Results from GWAS are beginning to reveal a 'missing heritability' in complex traits and diseases. Systematic, hypothesis-free analysis of epistatic interaction (GWIA) may help to close this increasingly recognized gap in heritability.

Hierarchical fine mapping of the cystic fibrosis modifier locus on 19q13 identifies an association with two elements near the genes CEACAM3 and CEACAM6

On 19q13, TGFB1 and the cystic fibrosis modifier 1 locus (CFM1) have been identified as modifiers of the course of the monogenic disease cystic fibrosis (CF). Recently, we have described a transmission disequilibrium at the microsatellite D19S197, localized between TGFB1 and CFM1. To map the corresponding molecular variants, we have selected informative SNP markers within a 600-kb area and compared two-marker-haplotype-distributions between phenotypically contrasting sib pair groups, intending to type only phylogenetically old markers by aiming for close-to-maximal polymorphism information content of the SNPs. Starting with a seed set of five SNPs that cover intermarker distances of up to 50 kb, we have iteratively added more SNPs to the map, until we could identify two genomic fragments of 3,289 and 2,052 bp for which pairs with contrasting phenotypes showed different haplotype distributions on the final 17-SNP-map (P(raw) = 0.0002, P(corr17SNPs) = 0.0106 and P(raw) = 0.0008, P(corr17SNPs) = 0.0469, respectively). Resequencing of these fragments of four unrelated individuals for each element showed that the mildly and severely affected pairs differ in seven SNPs and concordant pairs differ from discordant pairs in five SNPs. Annotation of these variants indicate that CEACAM6 and a regulatory element near the 3' end of CEACAM3 are associated with CF disease severity and intrapair discordance, respectively. While our approach was only guided by the markers' position, the involvement of genes from the CEACAM family in host defense and innate immunity designates these proteins as likely modifiers of the multi-organ disease cystic fibrosis which is known for its cytokine imbalance and pro-inflammatory phenotype.

Genome-wide association study of alcohol dependence

CONTEXT

Alcohol dependence is a serious and common public health problem. It is well established that genetic factors play a major role in the development of this disorder. Identification of genes that contribute to alcohol dependence will improve our understanding of the mechanisms that underlie this disorder.

OBJECTIVE

To identify susceptibility genes for alcohol dependence through a genome-wide association study (GWAS) and a follow-up study in a population of German male inpatients with an early age at onset.

DESIGN

The GWAS tested 524,396 single-nucleotide polymorphisms (SNPs). All SNPs with P < 10(-4) were subjected to the follow-up study. In addition, nominally significant SNPs from genes that had also shown expression changes in rat brains after long-term alcohol consumption were selected for the follow-up step.

SETTING

Five university hospitals in southern and central Germany.

PARTICIPANTS

The GWAS included 487 male inpatients with alcohol dependence as defined by the DSM-IV and an age at onset younger than 28 years and 1358 population-based control individuals. The follow-up study included 1024 male inpatients and 996 age-matched male controls. All the participants were of German descent.

MAIN OUTCOME MEASURES

Significant association findings in the GWAS and follow-up study with the same alleles.

RESULTS

The GWAS produced 121 SNPs with nominal P < 10(-4). These, together with 19 additional SNPs from homologues of rat genes showing differential expression, were genotyped in the follow-up sample. Fifteen SNPs showed significant association with the same allele as in the GWAS. In the combined analysis, 2 closely linked intergenic SNPs met genome-wide significance (rs7590720, P = 9.72 x 10(-9); rs1344694, P = 1.69 x 10(-8)). They are located on chromosome region 2q35, which has been implicated in linkage studies for alcohol phenotypes. Nine SNPs were located in genes, including the CDH13 and ADH1C genes, that have been reported to be associated with alcohol dependence.

CONCLUSIONS

This is the first GWAS and follow-up study to identify a genome-wide significant association in alcohol dependence. Further independent studies are required to confirm these findings.

Characterisation of psoriasis susceptibility locus 6 (PSORS6) in patients with early onset psoriasis and evidence for interaction with PSORS1

BACKGROUND

Psoriasis is a genetically complex, chronic inflammatory skin disease. The authors have previously identified a susceptibility locus on chromosome 19p13 (PSORS6).

METHODS AND RESULTS

In a follow-up linkage disequilibrium (LD) study in an independent family based cohort, the authors found evidence for association to a newly discovered microsatellite at this locus (D19SPS21, p<5.3x10(-5)). An LD based association scan in 300 trios revealed association to several single, single nucleotide polymorphisms (SNPs) in one LD block. When the authors stratified this cohort for carrying the PSORS1 risk allele at the HLA-C locus, evidence for association became much stronger at single SNP and haplotype levels (p values between 1.0x10(-4) and 8.0x10(-4)). In a replication study of 1114 patients and 937 control individuals, evidence for association was also observed after stratification to the PSORS1 risk allele. In both study groups, logistic regression showed evidence for interaction between the risk alleles at PSORS1 and PSORS6. Best p values for rs12459358 in both study groups remained significant after correction for multiple testing. The associated LD block did not comprise any known genes. Interestingly, an adjacent gene, MUC16, coding for a large glycosylated protein expressed in epithelia and of unknown function, could be shown to be also expressed in tissues relevant for pathogenesis of psoriasis such as skin and thymus. Immunohistochemical analyses of skin revealed focal staining for MUC16 in suprabasal epidermal cells. Further functional studies are required to clarify its potential role in psoriasis and identify the causal variant(s) at this locus.

CONCLUSION

The data establish PSORS6 as a confirmed psoriasis susceptibility locus showing interaction with PSORS1.

Genome-wide SNP-based linkage scan identifies a locus on 8q24 for an age-related hearing impairment trait

Age-related hearing impairment (ARHI), or presbycusis, is a very common multifactorial disorder. Despite the knowledge that genetics play an important role in the etiology of human ARHI as revealed by heritability studies, to date, its precise genetic determinants remain elusive. Here we report the results of a cross-sectional family-based genetic study employing audiometric data. By using principal component analysis, we were able to reduce the dimensionality of this multivariate phenotype while capturing most of the variation and retaining biologically important features of the audiograms. We conducted a genome-wide association as well as a linkage scan with high-density SNP microarrays. Because of the presence of genetic population substructure, association testing was stratified after which evidence was combined by meta-analysis. No association signals reaching genome-wide significance were detected. Linkage analysis identified a linkage peak on 8q24.13-q24.22 for a trait correlated to audiogram shape. The signal reached genome-wide significance, as assessed by simulations. This finding represents the first locus for an ARHI trait.

Single-nucleotide polymorphisms of MMP-2 gene in stroke subtypes

BACKGROUND

Matrix metalloproteinases (MMP) are expressed after ischemic stroke. These proteases are responsible for a higher incidence of hemorrhages, are correlated to size of infarction and influence the effects of recombinant tissue plasminogen activator treatment. We therefore evaluated single nucleotide polymorphisms (SNP) of MMP-2 in different subtypes of stroke patients in an association study using a case-control design.

METHODS

197 stroke patients were divided according to modified TOAST criteria (small vessel disease, large vessel disease, hemorrhagic stroke and asymptomatic carotid artery stenosis) and compared to 143 controls. Clinical data like age, sex, risk factors and diagnostic results including MRI or cranial CT scans and ultrasound evaluations of intra- and extracranial arteries were obtained. Genotypes of MMP-2 (12 SNP) were compared to controls and DNA samples were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis. Logistic regression analysis was performed for small vessel disease to test for interactions between markers and defined clinical risk factors. Additionally, MMP-2 serum levels obtained in the first 24 h after stroke were measured.

RESULTS

From the MMP-2 gene, 5 markers (rs1030868, rs2241145, rs2287074, rs2287076, rs7201) showed a significant association with small vessel infarcts (p < 0.05) and rs7201:g.C was identified as an independent risk factor by multivariable logistic regression analysis. MMP-2 protein levels were significantly lower in this group (174 +/- 48 ng/dl) versus controls (214 +/- 56 ng/dl). For other stroke subtypes, no significant association with MMP-2 SNP could be found.

CONCLUSION

Our study demonstrates an association of the MMP-2 gene with the development of lacunar stroke, and no association of MMP-2 with other stroke subtypes.

Occupational noise, smoking, and a high body mass index are risk factors for age-related hearing impairment and moderate alcohol consumption is protective: a European population-based multicenter study

A multicenter study was set up to elucidate the environmental and medical risk factors contributing to age-related hearing impairment (ARHI). Nine subsamples, collected by nine audiological centers across Europe, added up to a total of 4,083 subjects between 53 and 67 years. Audiometric data (pure-tone average [PTA]) were collected and the participants filled out a questionnaire on environmental risk factors and medical history. People with a history of disease that could affect hearing were excluded. PTAs were adjusted for age and sex and tested for association with exposure to risk factors. Noise exposure was associated with a significant loss of hearing at high sound frequencies (>1 kHz). Smoking significantly increased high-frequency hearing loss, and the effect was dose-dependent. The effect of smoking remained significant when accounting for cardiovascular disease events. Taller people had better hearing on average with a more pronounced effect at low sound frequencies (<2 kHz). A high body mass index (BMI) correlated with hearing loss across the frequency range tested. Moderate alcohol consumption was inversely correlated with hearing loss. Significant associations were found in the high as well as in the low frequencies. The results suggest that a healthy lifestyle can protect against age-related hearing impairment.

Investigation of promoter variations in dendritic cell-specific ICAM3-grabbing non-integrin (DC-SIGN) (CD209) and their relevance for human cytomegalovirus reactivation and disease after allogeneic stem-cell transplantation

Promoter variations in Toll-like receptor genes (n = 7) and genes encoding pathogen recognition and virus entry receptors (n = 7) were screened to detect any association with human cytomegalovirus (hCMV) reactivation and disease in patients following allogeneic stem-cell transplantation. Two single nucleotide polymorphisms (rs735240, G>A; rs2287886, C>T) in the promoter region of the dendritic cell-specific ICAM3-grabbing non-integrin (DC-SIGN) showed a significant association with an increased risk of development of hCMV reactivation and disease. Furthermore, these genetic markers influenced the expression levels of DC-SIGN on immature dendritic cells, as well as the infection efficiency of immature dendritic cells by hCMV, as determined by hCMV immediate-early antigen staining. Screening of patients following allogeneic stem-cell transplantation for the presence of these defined genetic polymorphisms might help to predict the individual risk of hCMV reactivation and disease.