Maria Dardioti

IL-1RN and IL-1B gene polymorphisms and cerebral hemorrhagic events after traumatic brain injury.

Objective: To investigate the association of (variable number tandem repeat) interleukin (IL) 1RN and (-511) IL-1B gene polymorphisms with brain hemorrhagic events after traumatic brain injury (TBI). Methods: Data from brain CT, Glasgow Coma Scale (GCS) at admission, and 6-month Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) were collected for 151 prospectively recruited patients with TBI. IL-1RN and IL-1B genotypes were determined using standard methods. Presence vs absence of any type of brain hemorrhage was the main outcome. Type of brain hemorrhage, GCS at admission, and 6-month GOS and mRS were secondary outcomes. Odd ratios (ORs) and corresponding 95% CI were calculated using logistic regression analyses. In adjusted models, the associations were controlled for age, gender, diffuse brain edema, volume of intracranial hematoma, neurosurgical intervention, and GCS at admission. p values less than 0.01 were considered significant. Results: Compared with noncarriers, IL-1RN allele 2 carriers had higher odds of having cerebral hemorrhages after TBI (adjusted OR = 4.57; 95% CI = 1.67 to 12.96; p = 0.004). The associations for (-511) IL-1B polymorphism were not significant. Conclusion: There is an association between the presence of interleukin-1RN allele 2 and posttraumatic brain hemorrhage.

Genetic association studies in osteonecrosis of the femoral head: mini review of the literature

Recent data suggest that osteonecrosis (ON) of the femoral head (FHON) is a multisystemic disease rather than a disease of the femoral head [1]. There are indications that ON may be the result of elevated marrow pressure, decreased blood supply, disturbed coagulation system or direct toxic effects on bone cells. In addition, diverse conditions have been implicated in the development of secondary ON, including corticosteroids, alcohol abuse, trauma, sickle cell disease, and metabolic, neoplastic and connective tissue disorders [2]. Idiopathic FHON in twins and a clustering of cases in families [3, 4] imply that genetic factors are involved. Increased incidence of ON in specific animal models also provides further evidence of the existence of susceptibility genes [5] (Table 1). Single gene defect osteonecrosis

AQP4 Tag Single Nucleotide Polymorphisms in Patients with Traumatic Brain Injury

Accumulating evidence suggests that the extent of brain injury and the clinical outcome after traumatic brain injury (TBI) are modulated, to some degree, by genetic variants. Aquaporin-4 (AQP4) is the predominant water channel in the central nervous system and plays a critical role in controlling the water content of brain cells and the development of brain edema after TBI. We sought to investigate the influence of the AQP4 gene region on patient outcome after TBI by genotyping tag single nucleotide polymorphisms (SNPs) along AQP4 gene. A total of 363 patients with TBI (19.6% female) were prospectively evaluated. Data including the Glasgow Coma Scale (GCS) scores at admission, the presence of intracranial hemorrhage, and the 6-month Glasgow Outcome Scale (GOS) scores were collected. Seven tag SNPs across the AQP4 gene were identified based on the HapMap data. Using logistic regression analyses, SNPs and haplotypes were tested for associations with 6-month GOS after adjusting for age, GCS score, and sex. Significant associations with TBI outcome were detected for rs3763043 (OR [95% confidence interval (CI)]: 5.15 [1.60-16.5], p=0.006, for recessive model), rs3875089 (OR [95% CI]: 0.18 [0.07-0.50] p=0.0009, for allele difference model), and a common haplotype of AQP4 tag SNPs (OR [95% CI]: 2.94, [1.34-6.36], p=0.0065). AQP4 tag SNPs were not found to influence the initial severity of TBI or the presence of intracranial hemorrhages. In conclusion, the present study provides evidence for possible involvement of genetic variations in AQP4 gene in the functional outcome of patients with TBI.

Angiotensin-converting enzyme tag single nucleotide polymorphisms in patients with intracerebral hemorrhage.

Objectives Studies investigating the association between angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and the risk of intracerebral hemorrhage (ICH) have provided conflicting results. Moreover, it is possible that the ACE I/D polymorphism may not represent the functional variant of the gene. The objective of this study was to clarify the influence of the ACE gene region on the risk of ICH by genotyping tag polymorphisms along ACE gene in two independent ethnically different cohorts. Methods We included 250 Greek and 169 Polish unrelated patients with ICH and 250 Greek and 322 Polish normal controls in the study. To cover the majority of the genetic variability across the extended ACE gene region, we identified five tag single nucleotide polymorphisms (rs4343, rs4461142, rs7221780, rs8066276, rs8066114) from the HapMap using a pairwise tagging approach and an r2 greater than or equal to 0.8. Single nucleotide polymorphisms and haplotypes were analyzed for associations with ICH risk, ICHsubtype (lobar/nonlobar), and age of disease onset using logistic and Cox regression models. Correction for multiple comparisons was carried out. Results In the Polish cohort, we observed a trend toward an association between the rs4461142 and the age of ICH onset (hazard ratio 0.50, 95% confidence interval 0.27–0.90, P=0.02). A common haplotype (GTCTC) also showed a trend for increased ICH risk in the Polish cohort (odds ratio 0.19, 95% confidence interval 0.04–0.85, P=0.02). These results were not replicated in the Greek cohort. Conclusions Our results did not provide clear evidence for a role of ACE gene in the development of ICH.

Alpha-1 Antichymotrypsin Gene Signal Peptide A/T Polymorphism and Primary Intracerebral Hemorrhage

Background/Aims: Alpha-1 antichymotrypsin (ACT), a serine proteinase inhibitor, has been implicated in vascular pathology. The TT genotype of the ACT signal peptide A/T polymorphism has been reported to confer susceptibility to primary intracerebral hemorrhage (PICH). We conducted a prospective study to test possible association of ACT signal peptide A/T polymorphism with PICH in a Greek cohort with enough power (80%) to detect a twofold increase in the odds ratio. Methods: We prospectively recruited 147 patients with PICH. ACT signal peptide A/T genotypes were determined in patients and 206 healthy, age- and sex-matched control subjects from the neurology outpatient clinic using the polymerase chain reaction restriction fragment length polymorphism method. Results: Our study did not show an association between ACT signal peptide A/T polymorphism and PICH. We also failed to find any influence on age at onset, the location and volume of PICH as well as on clinical severity at admission or 6-month outcome. Conclusion: Our data failed to confirm an association between ACT signal peptide A/T polymorphism and PICH. However, we cannot exclude the possibility that the TT genotype confers susceptibility at less than a twofold increase.

Effect of angiotensin-converting enzyme tag single nucleotide polymorphisms on the outcome of patients with traumatic brain injury.

Background Genetic variants appear to influence, at least to some degree, the extent of brain injury and the clinical outcome of patients who have sustained a traumatic brain injury (TBI). Angiotensin-converting enzyme (ACE) is a zinc metallopeptidase that is implicated in the regulation of blood pressure and cerebral circulation. ACE gene polymorphisms were found to regulate serum ACE enzyme activity. Objective The present study aimed to investigate possible influence of ACE gene region variants on patients’ outcome after TBI. Patients and methods In total, 363 TBI patients prospectively enrolled in the study were genotyped for five tag single nucleotide polymorphisms (SNPs) across the ACE gene. Using logistic regression analyses, tag SNPs and their constructed haplotypes were tested for associations with 6-month Glasgow Outcome Scale scores, after adjustment for age, sex, Glasgow Coma Scale scores at admission, and the presence of a hemorrhagic event in the initial computed tomography scan. Results Significant effects on TBI outcome were found for three neighboring tag SNPs in the codominant (genotypic) model of inheritance [rs4461142: odds ratio (OR) 0.26, 95% confidence interval (CI) 0.12–0.57, P=0.0001; rs7221780: OR 2.67, 95% CI 1.25–5.72, P=0.0003; and rs8066276: OR 3.82, 95% CI 1.80–8.13, P=0.0002; for the heterozygous variants compared with the common alleles]. None of the constructed common tag SNPs haplotypes was associated with TBI outcome. Conclusion The present study provides evidence of the possible influence of genetic variations in a specific region of the ACE gene on the outcome of TBI patients. This association may have pharmacogenetic implications in identifying those TBI patients who may benefit from ACE inhibition.

CpG Island Methylation Patterns in Relapsing-Remitting Multiple Sclerosis

AbstractDNA methylation may predispose to multiple sclerosis (MS), as aberrant methylation in the promoter regions across the genome seems to underlie several processes of MS. We have currently determined the methylation status of eight genes in relapsing-remitting MS patients. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was used to determine the status of 31 CpG islands, located across eight genes, in 33 healthy individuals and 66 MS patients (33 in relapse and 33 in remission). The methylation levels in the examined sites ranged from 0 to 31%. Methylation positivity for RUNX3 and CDKN2A differed significantly between MS patients and healthy controls. Maximum methylation in RUNX3, CDKN2A, SOCS1, and NEUROG1 genes was significantly different between patients and controls. Roc curves demonstrated that the appropriate cut-offs to distinguish patients from healthy controls were 2% for RUNX3 (OR 3.316, CI 1.207–9.107, p = 0.024) and 3% for CDKN2A (OR 3.077, CI 1.281–7.39, p = 0.018). No difference in methylation was observed between patients in relapse and patients in remission, in any of the genes examined. Methylation patterns of RUNX3 and CDKN2A may be able to distinguish between MS patients and healthy controls, but not between MS patients in relapse and in remission. Graphical AbstractMethylation patterns of RUNX3 and CDKN2A may be able to discriminate healthy individuals from MS patients.

Replication study of GWAS risk loci in Greek multiple sclerosis patients

ObjectivesTo validate in an ethnically homogeneous Greek multiple sclerosis (MS) cohort, genetic risk factors for the disease, identified through a number of previous multi-ethnic genome-wide association studies (GWAS).MethodsA total of 1228 MS cases and 1014 controls were recruited in the study, from 3 MS centers in Greece. We genotyped 35 susceptibility SNPs that emerged from previous GWAS or meta-analyses of GWAS. Allele and genotype single locus regression analysis, adjusted for gender and site, was performed. Permutation testing was applied to all analyses.ResultsSix polymorphisms reached statistical significance (permutation p value < 0.05). In particular, rs2760524 of LOC105371664, near RGS1 (permutation p value 0.001), rs3129889 of HLA-DRA, near HLA-DRB1 (permutation p value < 1.00e-04), rs1738074 of TAGAP (permutation p value 0.007), rs703842 of METTL1/CYP27B1 (permutation p value 0.008), rs9596270 of DLEU1 (permutation p value < 1.00e-04), and rs17445836 of LincRNA, near IRF8 (permutation p value 0.001) were identified as susceptibility risk factors in our group.ConclusionThe current study replicated a number of GWAS susceptibility SNPs, which implies that some similarities between the examined Greek population and the MS genetic architecture of the GWAS populations do exist.