Variants of the elastin (ELN) gene and susceptibility to intracranial aneurysm: a synthesis of genetic association studies using a genetic model-free approach.

BACKGROUND: The presence of an intracranial aneurysm (IA) is thought to have a genetic origin. The genetic association studies (GAS) that investigated the association between IA and elastin gene (ELN) variants have produced contradictory or inconclusive results. MATERIALS AND METHODS: In order to decrease the uncertainty of estimated genetic risk effects, a meta-analysis of published GAS-related variants in the ELN gene (ELN INT20 1315T > C, EX20 1264G > A, INT23 1501 + 24T > C and INT4 196 + 71G > A) with susceptibility to IA was conducted using a genetic model-free approach. The risk effects were estimated using the generalized odds ratio (ORG) metric. RESULTS: The analysis showed significant association for the INT20 1315T > C variant [ORG = 0.66 (0.45-0.95)], indicating a protection effect. For the variants EX20 1264G > A, INT23 1501 + 24T > C and INT4 196 + 71G > A, no statistically significant association with IAs was found. CONCLUSION: There is evidence that the ELN variant INT20 1315T > C is implicated in the development of IA; however, the results should be interpreted with caution since the number of published studies is limited.

Analysis of convergence of linkage and association studies in autism spectrum disorders.

Autism spectrum disorder (ASD) is a clinically and genetically heterogeneous group of pervasive neurodevelopmental disorders with a strong hereditary component. Although genome-wide linkage studies (GWLS) and [genome-wide association studies (GWAS)] have previously identified hundreds of ASD risk gene loci, the results remain inconclusive. In this study, a genomic convergence approach of GWAS and GWLS for ASD was implemented for the first time in order to identify genomic loci supported by both methods. A database with 32 GWLS and five GWAS for ASD was created. Convergence was quantified as the proportion of significant GWAS markers located within linked regions. Convergence was not found to be significantly higher than expected by chance (z-test = 1,177, P = 0,239). Although convergence is supportive of genuine effects, the lack of agreement between GWLS and GWAS is also indicative that these studies are designed to answer different questions and are not equally well suited for deciphering the genetics of complex traits.

Identification of Chromosomal Regions Linked to Autism-Spectrum Disorders: A Meta-Analysis of Genome-Wide Linkage Scans.

Background: Autism spectrum disorder (ASD) is a clinically and genetically heterogeneous group of pervasive neurodevelopmental disorders with a strong hereditary component. Although, genome-wide linkage scans (GWLS) and association studies (GWAS) have previously identified hundreds of ASD risk gene loci, the results remain inconclusive. Method: We performed a heterogeneity-based genome search meta-analysis (HEGESMA) of 15 genome scans of autism and ASD. Results: For strictly defined autism, data were analyzed across six separate genome scans. Region 7q22-q34 reached statistical significance in both weighted and unweighted analyses, with evidence of significantly low between-scan heterogeneity. For ASDs (data from 12 separate scans), chromosomal regions 5p15.33-5p15.1 and 15q22.32-15q26.1 reached significance in both weighted and unweighted analyses but did not reach significance for either low or high heterogeneity. Region 1q23.2-1q31.1 was significant in unweighted analyses with low between-scan heterogeneity. Finally, region 8p21.1-8q13.2 reached significant linkage peak in all our meta-analyses. When we combined all available genome scans (15), the same results were produced. Conclusions: This meta-analysis suggests that these regions should be further investigated for autism susceptibility genes, with the caveat that autism spectrum disorders have different linkage signals across genome scans, possibly because of the high genetic heterogeneity of the disease.

Synthesis of genetic association studies on autism spectrum disorders using a genetic model-free approach.

BACKGROUND: Autism spectrum disorder (ASD) is a clinically and genetically heterogeneous group of neurodevelopmental disorders. Despite the extensive efforts of scientists, the etiology of ASD is far from completely elucidated. In an effort to enlighten the genetic architecture of ASDs, a meta-analysis of all available genetic association studies (GAS) was conducted. METHODS: We searched in the Human Genome Epidemiology Navigator (HuGE Navigator) and PubMed for available case-control GAS of ASDs. The threshold for meta-analysis was two studies per genetic variant. The association between genotype distribution and ASDs was examined using the generalized linear odds ratio (ORG). For variants with available allele frequencies, the examined model was the allele contrast. RESULTS: Overall, 57 candidate genes and 128 polymorphisms were investigated in 159 articles. In total 28 genetic polymorphisms have been shown to be associated with ASDs, that are harbored in 19 genes. Statistically significant results were revealed for the variants of the following genes adenosine deaminase (ADA), bone marrow stromal cell antigen-1 (CD157/BST1), Dopamine receptor D1 (DRD1), engrailed homolog 2 (EN2), met proto-oncogene (MET), methylenetetrahydrofolate reductase (MTHFR), solute carrier family 6 member 4 (SLC6A4), Synaptosomal-associated protein, 25kDa (SNAP-25) and vitamin D receptor (VDR). In the allele contrast model of cases versus healthy controls, significant associations were observed for Adrenoceptor Alpha 1B (ADRA1B), acetyl serotonin O - methyltransferase (ASMT), complement component 4B (C4B), dopamine receptor D3 (DRD3), met proto-oncogene (MET), neuroligin 4, X-linked (NLGN4), neurexin 1 (NRXN1), oxytocin receptor (OXTR), Serine/Threonine-Protein Kinase PFTAIRE-1 (PFTK1), Reelin (RELN) and Ras-like without CAAX 2 (RIT2). CONCLUSION: These significant findings provide further evidence for genetic factors' implication in ASDs offering new perspectives in means of prevention and prognosis.

Assessment of the relative effectiveness and tolerability of treatments of type 2 diabetes mellitus: a network meta-analysis.

PURPOSE: The relative effectiveness and tolerability of treatments for type 2 diabetes mellitus (T2DM) is not well understood because few randomized, controlled trials (RCTs) have compared these treatments directly. The purpose of the present study was to evaluate the relative effectiveness and tolerability of treatments of T2DM. METHODS: We performed a network meta-analysis of available RCTs with pharmacologic interventions in T2DM and compared antidiabetic drugs and combination regimens with metformin (the reference drug). Glycemic control (proportion achieving HbA1c goal) and tolerability (risk of hypoglycemia) were the primary outcomes of interest. Direct and indirect relative effects (unadjusted) were expressed as odds ratios and 95% CIs. FINDINGS: Eight treatments (glucagon-like peptide-1 [GLP-1] agonists plus metformin, sulfonylureas plus metformin, dipeptidyl peptidase-4 [DPP-4] inhibitors] plus metformin, colesevelan plus metformin, thiazolidinediones plus metformin, meglitinides plus metformin, α-glucosidase inhibitor plus metformin, and rosiglitazone monotherapy) outperformed metformin (direct effects). Triple combinations of GLP-1, thiazolinedione, insulin, metiglinide, or sulfonylureas added to a metformin backbone improved glycemic control (indirect effects). Higher risk of hypoglycemia was noted for sulfonylureas, α-glycosidases, and metiglinides when added to metformin (direct effects). Across indirect effects, only 17% of comparisons yielded less risk of hypoglycemia (70% were worse and 13% were comparable). IMPLICATIONS: Our results point out the relative superiority of 2- and 3-drug combination regimens over metformin and summarize treatment effects and tolerability in a comprehensive manner, which adds to our knowledge regarding T2DM treatment options.

Assessing the relative effectiveness and tolerability of treatments in small cell lung cancer: a network meta-analysis.

BACKGROUND: The combination of Cisplatin plus Etoposide (EP) is currently the standard treatment for small cell lung cancer (SCLC). However, a large number of alternative treatments (monotherapies and combinations) have been studied in randomized controlled trials (RCTs) to identify more effective treatments. Aim of the present study was to assess the relative effectiveness and tolerability of these treatments. METHODS: PubMed, EMBASE and Cochrane Central Register of Controlled Trials were systematically searched to identify all RCTs that compared treatments for SCLC. Then, effectiveness of the treatments relative to the combination of Cisplatin plus Etoposide, reference treatment) was estimated by performing a network of treatments analysis. The analysis evaluated two efficacy outcomes (complete response - CR and objective response rate - ORR) and two tolerability outcomes (neutropenia and febrile neutropenia). All RCTs that provided data for calculating the odds ratios (OR) for the selected outcomes were considered. The network analysis involved direct and indirect analyses. RESULTS: We identified 71 articles eligible for inclusion, involving 91 different treatments. In total, 16,026 patients were included in the analysis. In the direct analysis the combination of Cisplatin plus Cyclophosphamide plus Etoposide plus Epirubicin showed better response than EP for the ORR outcome, but with worse tolerability (presence of neutropenia). The indirect analysis revealed that the combination of Cisplatin plus Doxorubicin plus Etoposide (plus Vincrisitine) showed better response that EP for the ORR outcome. CONCLUSIONS: No therapy shows better response for the two efficacy outcomes (CR and ORR); though, Cisplatin plus Doxorubicin plus Etoposide plus Vincrisitine might be a promising therapy for SCLC. The results should be interpreted with caution because the network was dominated by indirect comparisons. Large scale head-to-head RCTs are needed to confirm the present findings.