Evaluating the regulatory function of non-coding autism-associated single nucleotide polymorphisms on gene expression in human brain tissue.

Common variants account for most of the estimated heritability associated with autism spectrum disorder (autism). Although several replicable single nucleotide polymorphisms (SNPs) for the condition have been detected using genome-wide association study (GWAS) methodologies, their pathophysiological relevance remains elusive. Examining this is complicated, however, as all detected loci are situated within non-coding regions of the genome. It is therefore likely that they possess roles of regulatory function as opposed to directly affecting gene coding sequences. To bridge the gap between SNP discovery and mechanistic insight, we applied a comprehensive bioinformatic pipeline to functionally annotate autism-associated polymorphisms and their non-coding linkage disequilibrium (i.e., non-randomly associated) partners. We identified 82 DNA variants of probable regulatory function that may contribute to autism pathogenesis. To validate these predictions, we measured the impact of 11 high-confidence candidates and their GWAS linkage disequilibrium partners on gene expression in human brain tissue from Autistic and non-Autistic donors. Although a small number of the surveyed variants exhibited measurable influence on gene expression as determined via quantitative polymerase chain reaction, these did not survive correction for multiple comparisons. Additionally, no significant genotype-by-diagnosis effects were observed for any of the SNP-gene associations. We contend that this may reflect an inability to effectively capture the modest, neurodevelopmental-specific impact of individual variants on biological dysregulation in available post-mortem tissue samples, as well as limitations in the existing autism GWAS data.

Integration of xeno-free single-cell cloning in CRISPR-mediated DNA editing of human iPSCs improves homogeneity and methodological efficiency of cellular disease modeling.

The capability to generate induced pluripotent stem cell (iPSC) lines, in tandem with CRISPR-Cas9 DNA editing, offers great promise to understand the underlying genetic mechanisms of human disease. The low efficiency of available methods for homogeneous expansion of singularized CRISPR-transfected iPSCs necessitates the coculture of transfected cells in mixed populations and/or on feeder layers. Consequently, edited cells must be purified using labor-intensive screening and selection, culminating in inefficient editing. Here, we provide a xeno-free method for single-cell cloning of CRISPRed iPSCs achieving a clonal survival of up to 70% within 7-10 days. This is accomplished through improved viability of the transfected cells, paralleled with provision of an enriched environment for the robust establishment and proliferation of singularized iPSC clones. Enhanced cell survival was accompanied by a high transfection efficiency exceeding 97%, and editing efficiencies of 50%-65% for NHEJ and 10% for HDR, indicative of the method's utility in stem cell disease modeling.

Generation of induced pluripotent stem cell lines from three individuals with autism spectrum disorder.

Uncovering the molecular mechanisms of autism spectrum disorder (autism) necessitates development of relevant experimental models that are capable of recapitulating features of the clinical phenotype. Using non-integrative episomal vectors, peripheral blood mononuclear cells derived from three unrelated individuals diagnosed with autism were reprogrammed to induced pluripotent stem cells (iPSCs). The resultant lines exhibited the expected cellular morphology, karyotype, and evidence of pluripotency. These iPSCs constitute a valuable resource to support investigations of the underlying aetiology of autism.

Association of MSY haplotype background with nonobstructive azoospermia is AZF-dependent: A case-control study.

Identifying causal genes of spermatogenic failure on the male-specific region of Y chromosome (MSY) has been a challenging process. Due to the nonrecombining nature of MSY, haplotype-based approaches have recently been shown to be promising in identifying associated MSY haplogroups. We conducted an MSY analysis of nonobstructive azoospermia (NOA) patients in a case-control setting (N = 278 and 105 respectively) to identify modal haplogroups strongly associated with NOA. Patients with AZF deletions (AZF+) and no AZF deletions (AZF-) were compared with the control group. Given the larger sample set of AZF- NOA patients, we further investigated the association based on histopathological severity, namely Sertoli cell-only syndrome and maturation arrest subtypes. We observed no significant enrichment of MSY haplogroups in AZF- azoospermic patients (or its subtypes). However, we observed a strongly significant association between haplogroup J2a* and AZF+ patients (FDR-corrected p = .0056; OR = 7.02, 95%CI 1.89 to 39.20), a haplogroup which also showed significant enrichment for AZFa/b deletions (p = 4x10-4 ). We conclude that unlike AZF+ patients, AZF- NOA are less likely to have an MSY causative factor with large effect size, thus indicating that the aetiology of AZF- NOA, and to some extent AZFc NOA, is more likely to be based on non-MSY factors.

Systems genetics of nonsyndromic orofacial clefting provides insights into its complex aetiology.

Nonsyndromic oral clefting (NSOC) is although one of the most common congenital disorders worldwide, its underlying molecular basis remains elusive. This process has been hindered by the overwhelmingly high level of heterogeneity observed. Given that hitherto multiple loci and genes have been associated with NSOC, and that complex diseases are usually polygenic and show a considerable level of missing heritability, we used a systems genetics approach to reconstruct the NSOC network by integrating human-based physical and regulatory interactome with whole-transcriptome microarray data. We show that the network component contains 53% (23/43) of the curated NSOC-implicated gene set and displays a highly significant propinquity (P < 0.0001) between genes implicated at the genomic level and those differentially expressed at the transcriptome level. In addition, we identified bona fide candidate genes based on topological features and dysregulation (e.g. ANGPTL4), and similarly prioritised genes at GWA loci (e.g. MYC and CREBBP), thus providing further insight into the underlying heterogeneity of NSOC. Gene ontology analysis results were consistent with the NSOC network being associated with embryonic organ morphogenesis and also hinted at an aetiological overlap between NSOC and cancer. We therefore recommend this approach to be applied to other heterogeneous complex diseases to not only provide a molecular framework to unify genes which may seem as disparate entities linked to the same disease, but to also predict and prioritise candidate genes for further validation, thus addressing the missing heritability.

Prevalence of candidemia and associated candida subtypes following severe sepsis in non-neutropenic critically ill patients.

BACKGROUND: Invasive candidiasis management through the rapid initiation of appropriate antifungal therapy has been shown to be associated with the better prognosis, improved clinical outcome and reduced mortality in critically ill patients. Therefore, selection of  an appropriate antifungal therapy should be based on the distribution of candida species and the pattern of antifungal resistance. This study aimed to assess the prevalence of candidemia and associated subtypes following severe sepsis in non-neutropenic critically ill patients. METHODS: This study was a cross-sectional study that was conducted on severe sepsis patients stayed at least seven days in intensive care unit. Patients less than 18 years old, pregnant and breastfeeding patients, immunocompromised patients, neutropenic patients, patients with concurrent use of antifungal medicines and cytotoxic agents were excluded.To asses the candidemia, one mililiter of patients' blood sample was collected. Sample analysis was performed by Real-Time PCR and high resolution melting curve analysis method. RESULTS: Thirty-one critically ill patients were recruited in this study over 12-month period. Candidemia with a detection limit of 100 pg per 0.2 ml blood sample was not recognized in any of the included patients. CONCLUSION: The present result indicates low incidence of candidemia in the targeted intensive care units, but other factors such as small sample size, exclusion of patients with compromised immune system and the low fungal load at the time of sampling may also account for our observation.

The Essentiality of Reporting Hardy-Weinberg Equilibrium Calculations in Population-Based Genetic Association Studies.

Population-based genetic association studies have proven to be a powerful tool in identifying genes implicated in many complex human diseases that have a huge impact on public health. An essential quality control step in such studies is to undertake Hardy-Weinberg equilibrium (HWE) calculations. Deviations from HWE in the control group may reflect important problems including selection bias, population stratification and genotyping errors. If HWE is violated, the inferences of these studies may thus be biased. We therefore aimed to examine the extent to which HWE calculations are reported in genetic association studies published in Cell Journal(Yakhteh)(Cell J). Using keywords pertaining to genetic association studies, eleven relevant articles were identified of which ten provided full genotypic data. The genotype distribution of 16 single nucleotide polymorphisms (SNPs) was re-analyzed for HWE by using three different methods where appropriate. HWE was not reported in 60% of all articles investigated. Among those reporting, only one article provided calculations correctly and in detail. Therefore, 90% of articles analyzed failed to provide sufficient HWE data. Interestingly, three articles had significant HWE deviation in their control groups of which one highly deviated from HWE expectations (P= 9.8×10(-12)). We thus show that HWE calculations are under-reported in genetic association studies published in this journal. Furthermore, the conclusions of the three studies showing significant HWE in their control groups should be treated cautiously as they may be potentially misleading. We therefore recommend that reporting of detailed HWE calculations should become mandatory for such studies in the future.