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Ferroptosis is a lipid peroxidation-dependent mechanism of regulated cell death known to suppress tumor proliferation and progression. Although several genetic and protein hallmarks have been identified in ferroptotic cell death, it remains challenging to fully characterize ferroptosis signaling pathways and to find suitable biomarkers. Moreover, changes taking place in the epigenome of ferroptotic cells remain poorly studied. In this context, we aimed to investigate the role of chromatin remodeler forkhead box protein A1 (FOXA1) in RSL3-treated multiple myeloma cells because, similar to ferroptosis, this transcription factor has been associated with changes in the lipid metabolism, DNA damage, and epithelial-to-mesenchymal transition (EMT). RNA sequencing and Western blot analysis revealed that FOXA1 expression is consistently upregulated upon ferroptosis induction in different in vitro and in vivo disease models. In silico motif analysis and transcription factor enrichment analysis further suggested that ferroptosis-mediated FOXA1 expression is orchestrated by specificity protein 1 (Sp1), a transcription factor known to be influenced by lipid peroxidation. Remarkably, FOXA1 upregulation in ferroptotic myeloma cells did not alter hormone signaling or EMT, two key downstream signaling pathways of FOXA1. CUT&RUN genome-wide transcriptional binding site profiling showed that GPX4-inhibition by RSL3 triggered loss of binding of FOXA1 to pericentromeric regions in multiple myeloma cells, suggesting that this transcription factor is possibly involved in genomic instability, DNA damage, or cellular senescence under ferroptotic conditions.Abstract Figure

Alzheimer's disease (AD) biomarkers represent several neurodegenerative processes, such as synaptic dysfunction, neuronal inflammation and injury, as well as amyloid pathology. We performed an exome-wide rare variant analysis of six AD biomarkers (β-amyloid, total/phosphorylated tau, NfL, YKL-40, and Neurogranin) to discover genes associated with these markers. Genetic and biomarker information was available for 480 participants from two studies: EMIF-AD and ADNI. We applied a principal component (PC) analysis to derive biomarkers combinations, which represent statistically independent biological processes. We then tested whether rare variants in 9576 protein-coding genes associate with these PCs using a Meta-SKAT test. We also tested whether the PCs are intermediary to gene effects on AD symptoms with a SMUT test. One PC loaded on NfL and YKL-40, indicators of neuronal injury and inflammation. Four genes were associated with this PC: IFFO1, DTNB, NLRC3, and SLC22A10. Mediation tests suggest, that these genes also affect dementia symptoms via inflammation/injury. We also observed an association between a PC loading on Neurogranin, a marker for synaptic functioning, with GABBR2 and CASZ1, but no mediation effects. The results suggest that rare variants in IFFO1, DTNB, NLRC3, and SLC22A10 heighten susceptibility to neuronal injury and inflammation, potentially by altering cytoskeleton structure and immune activity disinhibition, resulting in an elevated dementia risk. GABBR2 and CASZ1 were associated with synaptic functioning, but mediation analyses suggest that the effect of these two genes on synaptic functioning is not consequential for AD development.

Recent studies have demonstrated genetic differences between monozygotic (MZ) twins. To test the hypothesis that early post-twinning mutational events associate with phenotypic discordance, we investigated a cohort of 13 twin pairs (n = 26) discordant for various clinical phenotypes using whole-exome sequencing and screened for copy number variation (CNV). We identified a de novo variant in PLCB1, a gene involved in the hydrolysis of lipid phosphorus in milk from dairy cows, associated with lactase non-persistence, and a variant in the mitochondrial complex I gene MT-ND5 associated with amyotrophic lateral sclerosis (ALS). We also found somatic variants in multiple genes (TMEM225B, KBTBD3, TUBGCP4, TFIP11) in another MZ twin pair discordant for ALS. Based on the assumption that discordance between twins could be explained by a common variant with variable penetrance or expressivity, we screened the twin samples for known pathogenic variants that are shared and identified a rare deletion overlapping ARHGAP11B, in the twin pair manifesting with either schizotypal personality disorder or schizophrenia. Parent-offspring trio analysis was implemented for two twin pairs to assess potential association of variants of parental origin with susceptibility to disease. We identified a de novo variant in RASD2 shared by 8-year-old male twins with a suspected diagnosis of autism spectrum disorder (ASD) manifesting as different traits. A de novo CNV duplication was also identified in these twins overlapping CD38, a gene previously implicated in ASD. In twins discordant for Tourette's syndrome, a paternally inherited stop loss variant was detected in AADAC, a known candidate gene for the disorder.

X-linked dystonia-parkinsonism (XDP) is a monogenic neurodegenerative disorder of the basal ganglia, which presents as a combination of hyperkinetic movements and parkinsonian features. The underlying genetic mechanism involves the insertion of a SINE-VNTR-Alu retrotransposon within the TAF1 gene. Interestingly, alterations of TAF1 have been involved in multiple neurological diseases. In XDP, the SINE-VNTR-Alu insertion in TAF1 has been proposed to result in alternative splicing defects, including the decreased incorporation of a neuron-specific microexon annotated as 34′. This mechanism has become controversial as recent studies failed to provide support. In order to resolve this conundrum, we examined the alternative splicing patterns of TAF1 mRNAs in XDP and control brains. The impact of the disease-associated SINE-VNTR-Alu on alternative splicing of microexon 34′ was further investigated in cellular assays. Subsequently, microexon 34′ incorporation was explored by RT-PCR and Nanopore long-read sequencing of TAF1 mRNAs from XDP and control brains tissues. Using cell-based splicing assays, we demonstrate that presence of the disease-associated SINE-VNTR-Alu does not affect the inclusion of microexon 34′. In addition, we show that (1) microexon 34′-containing TAF1 mRNAs are detected at similar levels in XDP as in controls and that (2) the architecture of TAF1 transcripts is remarkably similar between XDP and controls brains. These results indicate that microexon 34′ incorporation into TAF1 mRNA is not affected in XDP brains. Our findings shift the current paradigm of XDP by discounting alternative splicing of TAF1 microexon 34′ as the molecular basis for this disease., Capponi et al.19 propose a paradigm shift for the pathogenesis of XDP by demonstrating that microexon 34′ is incorporated within TAF1 mRNA in XDP brain specimens., Graphical Abstract Graphical abstract

Long-read sequencing has substantial advantages for structural variant discovery and phasing of variants compared to short-read technologies, but the required and optimal read length has not been assessed. In this work, we used long reads simulated from human genomes and evaluated structural variant discovery and variant phasing using current best practice bioinformatics methods. We determined that optimal discovery of structural variants from human genomes can be obtained with reads of minimally 20 kb. Haplotyping variants across genes only reaches its optimum from reads of 100 kb. These findings are important for the design of future long-read sequencing projects.

Long read sequencing has a substantial advantage for structural variant discovery and phasing of variants compared to short-read technologies, but the required and optimal read length has not been assessed. In this work, we used simulated long reads and evaluated structural variant discovery and variant phasing using current best practice bioinformatics methods. We determined that optimal discovery of structural variants from human genomes can be obtained with reads of minimally 15 kbp. Haplotyping genes entirely only reaches its optimum from reads of 100 kbp. These findings are important for the design of future long read sequencing projects.

Technological limitations have hindered the large-scale genetic investigation of tandem repeats in disease. We show that long-read sequencing with a single Oxford Nanopore Technologies PromethION flow cell per individual achieves 30× human genome coverage and enables accurate assessment of tandem repeats including the 10,000-bp Alzheimer’s disease-associated ABCA7 VNTR. The Guppy “flip-flop” base caller and tandem-genotypes tandem repeat caller are efficient for large-scale tandem repeat assessment, but base calling and alignment challenges persist. We present NanoSatellite, which analyzes tandem repeats directly on electric current data and improves calling of GC-rich tandem repeats, expanded alleles, and motif interruptions.

Summary Researchers commonly use spreadsheet software Microsoft Excel to view, edit and format tabor comma-separated data files, for example to prepare supplementary data for a paper. When loading such a file Excel converts values that it interprets as dates or numbers into an internal format, sometimes corrupting the data in this process by e.g. changing some gene names to dates. Unfortunately these overzealous “smart” features cannot be turned off and have been causing errors in a substantial number of published supplementary data files. Opentsv was made to effectively circumvent this problem at the root. It provides an easy and transparent way to open delimited data files in Excel without these conversions. Availability and Implementation Opentsv is freely available as a tclkit based single file executable for Windows at https://github.com/derijkp/opentsv. The source code is available under the MIT license.

Purpose: Homozygosity mapping is an effective approach for detecting molecular defects in consanguineous families by delineating stretches of genomic DNA that are identical by descent. Constant developments in next-generation sequencing created possibilities to combine whole-exome sequencing (WES) and homozygosity Mapping in a single step. Methods: Basic optimization of homozygosity mapping parameters was performed in a group of families with autosomal-recessive (AR) mutations for which both single-nucleotide polymorphism (SNP) array and WES data were available. We varied the criteria for SNP extraction and PLINK thresholds to estimate their effect on the accuracy of homozygosity mapping based on WES. Results: Our protocol showed high specificity and sensitivity for homozygosity detection and facilitated the identification of novel mutations in GAN, GBA2, and ZFYVE26 in four families affected by hereditary spastic paraplegia or Charcot-Marie-Tooth disease. Filtering and mapping with optimized parameters was integrated into the HOMWES (homozygosity mapping based on WES analysis) tool in the GenomeComb package for genomic data analysis. Conclusion: We present recommendations for detection of homozygous regions based on WES data and a bioinformatics tool for their identification, which can be widely applied for studying AR disorders.

Genetic variants in or near miRNA genes can have profound effects on miRNA expression and targeting. As user-friendly software for the impact prediction of miRNA variants on a large scale is still lacking, we created a tool called miRVaS. miRVaS automates this prediction by annotating the location of the variant relative to functional regions within the miRNA hairpin (seed, mature, loop, hairpin arm, flanks) and by annotating all predicted structural changes within the miRNA due to the variant. In addition, the tool defines the most important region that is predicted to have structural changes and calculates a conservation score that is indicative of the reliability of the structure prediction. The output is presented in a tab-separated file, which enables fast screening, and in an html file, which allows visual comparison between wild-type and variant structures. All separate images are provided for downstream use. Finally, we tested two different approaches on a small test set of published functionally validated genetic variants for their capacity to predict the impact of variants on miRNA expression.

From a number of genome-wide association studies it was shown that de novo and/or rare copy number variants (CNVs) are found at an increased frequency in neuropsychiatric diseases. In this study we examined the prevalence of CNVs in six genomic regions (1q21.1, 2p16.3, 3q29, 15q11.2, 15q13.3, and 16p11.2) previously implicated in neuropsychiatric diseases. Hereto, a cohort of four neuropsychiatric disorders (schizophrenia, bipolar disorder, major depressive disorder, and intellectual disability) and control individuals from three different populations was used in combination with Multilpex Amplicon Quantifiaction (MAQ) assays, capable of high resolution (kb range) and custom-tailored CNV detection. Our results confirm the etiological candidacy of the six selected CNV regions for neuropsychiatric diseases. It is possible that CNVs in these regions can result in disturbed brain development and in this way lead to an increased susceptibility for different neuropsychiatric disorders, dependent on additional genetic and environmental factors. Our results also suggest that the neurodevelopmental component is larger in the etiology of schizophrenia and intellectual disability than in mood disorders. Finally, our data suggest that deletions are in general more pathogenic than duplications. Given the high frequency of the examined CNVs (12%) in patients of different neuropsychiatric disorders, screening of large cohorts with an affordable and feasible method like the MAQ assays used in this study is likely to result in important progress in unraveling the genetic factors leading to an increased susceptibility for several psychiatric disorders. (c) 2012 Wiley Periodicals, Inc.

Background: The rs1344706 single nucleotide polymorphism in the ZNF804A gene is a common variant with strong evidence for association with schizophrenia. Recent studies show an association of rs1344706 with cognitive functioning, and there is some evidence suggesting that the risk allele may increase susceptibility for a subtype of schizophrenia with relatively spared cognition. Methods: We tested the effect of rs1344706 genotype in 89 schizophrenia patients on 3 basic cognitive domains (working memory, processing speed and attention) shown to be severely impaired in schizophrenia. Also we investigated the effect of rs1344706 on the severity of neurological soft signs, subtle impairments in motor and sensory functions highly frequent in schizophrenia patients. Neurological soft signs and cognitive deficits are central features of schizophrenia and are tightly linked with clinical, social and functional outcome. Results: Our results show an association of higher rs1344706 risk allele load with improved performance on processing speed and with fewer neurological soft signs. Conclusions: Together with other studies, our findings suggest that ZNF804A is associated with a subtype of schizophrenia with better cognitive and neurological functioning. Discovery of the specific pathways through which ZNF804A is exerting this effect may lead to better prevention, diagnosis and treatment for a specific group of schizophrenia patients.

Through active reuptake of serotonin into presynaptic neurons, the serotonin transporter (5-HTT) plays an important role in regulating serotonin concentrations in the brain, and it is the site of binding for tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs). Therefore it has been hypothesized that this transporter is involved in the etiology of bipolar (BP) disorder. Inconsistent association study results for the SLC6A4 gene encoding 5-HTT reported in literature emphasize the need for more systematic and detailed analyses of this candidate gene. We performed an extensive analysis of SLC6A4 on DNA of 254 BPI patients and 364 control individuals from a Northern Swedish isolated population. This analysis consisted of a HapMap LD-based association study including three widely investigated polymorphisms (5-HTTVNTR, 5-HTTLPR, and rs3813034), a copy-number variation (CNV) analysis and a mutation analysis of the complete coding sequence and the 3-UTR of SLC6A4. No single marker showed statistically significant association with BPI, nor did any of the haplotypes. In the mutation analysis 13 novel variants were detected, including 2 amino acid substitutions M389V and I587L, but these are probably not implicated in risk for BP. No deletions or duplications were detected in the CNV analysis. We conclude that variation in the SLC6A4 gene or its regulatory regions does not contribute to the susceptibility for BP disorder in the Northern Swedish population.

Robust statistical, genetic and functional evidence supports a role for DISC1 in the aetiology of major mental illness. Furthermore, many of its protein-binding partners show evidence for involvement in the pathophysiology of a range of neurodevelopmental and psychiatric disorders. Copy number variants (CNVs) are suspected to play an important causal role in these disorders. In this study, CNV analysis of DISC1 and its binding partners PAFAH1B1, NDE1, NDEL1, FEZ1, MAP1A, CIT and PDE4B in Scottish and Northern Swedish population-based samples was carried out using multiplex amplicon quantification. Here, we report the finding of rare CNVs in DISC1, NDE1 (together with adjacent genes within the 16p13.11 duplication), NDEL1 (including the overlapping MYH10 gene) and CIT. Our findings provide further evidence for involvement of DISC1 and its interaction partners in neuropsychiatric disorders and also for a role of structural variants in the aetiology of these devastating diseases.

Aminoacyl-tRNA synthetases are ubiquitously expressed proteins that charge tRNAs with their cognate amino acids. By ensuring the fidelity of protein synthesis, these enzymes are essential for the viability of every cell. Yet, mutations in six tRNA synthetases specifically affect the peripheral nerves and cause Charcot-Marie-Tooth (CMT) disease. The CMT-causing mutations in tyrosyl- and glycyl-tRNA synthetases (YARS and GARS, respectively) alter the activity of the proteins in a range of ways (some mutations do not impact charging function, while others abrogate it), making a loss of function in tRNA charging unlikely to be the cause of disease pathology. It is currently unknown which cellular mechanisms are triggered by the mutant enzymes and how this leads to neurodegeneration. Here, by expressing two pathogenic mutations (G240R, P234KY) in Drosophila, we generated a model for GARS-associated neuropathy. We observed compromised viability, and behavioral, electrophysiological and morphological impairment in flies expressing the cytoplasmic isoform of mutant GARS. Their features recapitulated several hallmarks of CMT pathophysiology and were similar to the phenotypes identified in our previously described Drosophila model of YARS-associated neuropathy. Furthermore, CG8316 and CG15599 - genes identified in a retinal degeneration screen to modify mutant YAKS, also modified the mutant GARS phenotypes. Our study presents genetic evidence for common mutant-specific interactions between two CMT-associated aminoacyl-tRNA synthetases, lending support for a shared mechanism responsible for the synthetase-induced peripheral neuropathies. (C) 2014 Elsevier Inc. All rights reserved.

Shiga toxin-producing E. coli (STEC), of various serogroups harboring the intimin gene, form a serious threat to human health. They are asymptomatically carried by cattle. In this study, a quantitative real-time PCR (qPCR) method was developed as a molecular method to detect and quantify Shiga toxin genes stx1 and stx2 and the intimin gene eae. Subsequently, 59 fecal samples from six farms were tested using qPCR and a culture method as a reference. Three farms had contaminated animals as demonstrated by the culture method. Culture-positive farms showed moderate significantly higher stx prevalences than culture-negative farms (p = 0.05). This is the first study which showed preliminary results that qPCR can predict STEC farm contamination, with a specificity of 77% and a sensitivity of 83%, as compared with the culture method. Furthermore, the presence or quantity of stx genes in feces was not correlated to the isolation of STEC from the individual animal. Quantitative data thus did not add value to the results. Finally, the detection of both stx and eae genes within the same fecal sample or farm using qPCR was not correlated with the isolation of an eae-harboring STEC strain from the respective sample or farm using the culture method.

The latest release of the large ribosomal subunit RNA database contains 429 sequences. All these sequences are aligned, and incorporate secondary structure information. The rRNA WWW Server at URL http://rrna.uia.ac.be/ provides researchers with an easily accessible resource to obtain the data in this database in a number of computer-readable formats. A new query interface has been added to the server. If necessary, the data can also be obtained by anonymous ftp from the same site.

Summary: We developed a modular software package SNPbox that automates and standardizes the generation of PCR primers and is used in the strategy for constructing single nucleotide polymorphisms (SNPs) maps. In this strategy, the focus of primer design can be either on the validation of annotated public SNPs or on the SNP discovery in exon regions or extended genomic regions, both by resequencing. SNPbox relies on Primer3 for the primer design and combines this program with other publicly available software tools such as BLAST, Spidey and RepeatMasker, and newly developed algorithms. Primer conditions were chosen such that PCR amplifications are uniform for each PCR amplicon facilitating the use of high-throughput genetic platforms. SNPbox can also be used for the design of primer sets for mutation analysis, STR marker genotyping and microarray oligo design. Of the 2500 primer sets designed by SNPbox, 95% successfully amplified genomic DNA under uniform PCR conditions. Availability: The software is available from the authors upon request. Contact: jurgen.delfavero@ua.ac.be Supplementary information: SNPbox_supplement.

Over the last years, genome-wide studies consistently showed an increased burden of rare copy number variants (CNVs) in schizophrenia patients, supporting the common disease, rare variant hypothesis in at least a subset of patients. We hypothesize that in families with a high burden of disease, and thus probably a high genetic load influencing disease susceptibility, rare CNVs might be involved in the etiology of schizophrenia. We performed a genome-wide CNV analysis in the index patients of eight families with multiple schizophrenia affected members, and consecutively performed a detailed family analysis for the most relevant CNVs. One index patient showed a DRD5 containing duplication. A second index patient presented with an NRXN1 containing deletion and two adjacent duplications containing MYT1L and SNTG2. Detailed analysis in the subsequent families showed segregation of the identified CNVs. With this study we show the importance of screening high burden families for rare CNVs, which will not only broaden our knowledge concerning the molecular genetic mechanisms involved in schizophrenia but also allow the use of the obtained genetic data to provide better clinical care to these families in general and to non-symptomatic causal CNV carriers in particular. (c) 2013 Wiley Periodicals, Inc.

The rs1344706 single nucleotide polymorphism in the ZNF804A gene is a common variant with strong evidence for association with schizophrenia. Recent studies show an association of rs1344706 with cognitive functioning, and there is some evidence suggesting that the risk allele may increase susceptibility for a subtype of schizophrenia with relatively spared cognition.We tested the effect of rs1344706 genotype in 89 schizophrenia patients on 3 basic cognitive domains (working memory, processing speed and attention) shown to be severely impaired in schizophrenia. Also we investigated the effect of rs1344706 on the severity of neurological soft signs, subtle impairments in motor and sensory functions highly frequent in schizophrenia patients. Neurological soft signs and cognitive deficits are central features of schizophrenia and are tightly linked with clinical, social and functional outcome.Our results show an association of higher rs1344706 risk allele load with improved performance on processing speed and with fewer neurological soft signs.Together with other studies, our findings suggest that ZNF804A is associated with a subtype of schizophrenia with better cognitive and neurological functioning. Discovery of the specific pathways through which ZNF804A is exerting this effect may lead to better prevention, diagnosis and treatment for a specific group of schizophrenia patients.

The GWAS-based association of CACNA1C with bipolar disorder (BPD) is one of the strongest genetic findings to date. CACNA1C belongs to the family of CACN genes encoding voltage-dependent calcium channels (VDCCs). VDCCs are involved in brain circuits and cognitive processes implicated in BPD and schizophrenia (SZ). Recently, it was shown that rare copy number variations (CNVs) are found at an increased frequency in SZ and to a lesser extent also in BPD, suggesting the involvement of CNVs in the causation of these diseases. We hypothesize that CNVs in CACN genes can influence the susceptibility to BPD, SZ, and/or schizoaffective disorder (SZA). A search for CNVs in eight CACN genes in a patient-control sample of European decent was performed. A total of 709 BP patients, 645 SZ patients, 189 SZA patients, and 1,470 control individuals were screened using the Multiplex Amplicon Quantification (MAQ) method. We found a rare, partial deletion of 35.7?kb in CACNA2D4 in two unrelated late onset bipolar I patients and in one control individual. All three deletions shared the same breakpoints removing exons 1726 of CACNA2D4, comprising part of the CACHE domain. Based on the data we cannot claim causality to BPD of the identified CACNA2D4 deletion but nevertheless this deletion can be important in unraveling the underlying processes leading to psychiatric diseases in general and BPD in particular. (C) 2012 Wiley Periodicals, Inc.

Distinguishing single-nucleotide variants (SNVs) from errors in whole-genome sequences remains challenging. Here we describe a set of filters, together with a freely accessible software tool, that selectively reduce error rates and thereby facilitate variant detection in data from two short-read sequencing technologies, Complete Genomics and Illumina. By sequencing the nearly identical genomes from monozygotic twins and considering shared SNVs as 'true variants' and discordant SNVs as 'errors', we optimized thresholds for 12 individual filters and assessed which of the 1,048 filter combinations were effective in terms of sensitivity and specificity. Cumulative application of all effective filters reduced the error rate by 290-fold, facilitating the identification of genetic differences between monozygotic twins. We also applied an adapted, less stringent set of filters to reliably identify somatic mutations in a highly rearranged tumor and to identify variants in the NA19240 HapMap genome relative to a reference set of SNVs.

We present BioGraph, a data integration and data mining platform for the exploration and discovery of biomedical information. The platform offers prioritizations of putative disease genes, supported by functional hypotheses. We show that BioGraph can retrospectively confirm recently discovered disease genes and identify potential susceptibility genes, outperforming existing technologies, without requiring prior domain knowledge. Additionally, BioGraph allows for generic biomedical applications beyond gene discovery. BioGraph is accessible at http://www.biograph.be.

In recent years, DISC1 has emerged as one of the most credible and best supported candidate genes for schizophrenia and related neuropsychiatric disorders. Furthermore, increasing evidence - both genetic and functional - indicates that many of its protein interaction partners are also involved in the development of these diseases. In this study, we applied a pooled sample 454 sequencing strategy, to explore the contribution of genetic variation in DISC1 and 10 of its interaction partners (ATF5, Grb2, FEZ1, LIS-1, PDE4B, NDE1, NDEL1, TRAF3IP1, YWHAE, and ZNF365) to schizophrenia susceptibility in an isolated northern Swedish population. Mutation burden analysis of the identified variants in a population of 486 SZ patients and 514 control individuals, revealed that non-synonymous rare variants with a MAF

Genome-wide association studies (GWAS) have identified dozens of risk loci for many complex disorders, including Crohn's disease(1,2). However, common disease-associated SNPs explain at most similar to 20% of the genetic variance for Crohn's disease. Several factors may account for this unexplained heritability(3-5), including rare risk variants not adequately tagged thus far in GWAS(6-8). That rare susceptibility variants indeed contribute to variation in multifactorial phenotypes has been demonstrated for colorectal cancer(9), plasma high-density lipoprotein cholesterol levels(10), blood pressure(11), type 1 diabetes(12), hypertriglyceridemia(13) and, in the case of Crohn's disease, for NOD2 (refs. 14,15). Here we describe the use of high-throughput resequencing of DNA pools to search for rare coding variants influencing susceptibility to Crohn's disease in 63 GWAS-identified positional candidate genes. We identify low frequency coding variants conferring protection against inflammatory bowel disease in IL23R, but we conclude that rare coding variants in positional candidates do not make a large contribution to inherited predisposition to Crohn's disease.

Evolutionary tress based on small ribosomal subunit RNA sequences yield a new perspective on eukaryote evolution. In agreement with classical views regarding evolution, animals, green plants, and fungi form monophyletic groups which seem to have originated nearly simultaneously. The evolution of these organisms took place in a relatively short time interval and is characterized by a massive diversification of life forms. In contrast, the dissimilarity among protoctist small ribosomal subunit RNA sequences is huge and exceeds the diversity seen in the entire prokaryotic world. Furthermore, some Protoctista branch off very soon in eukaryote evolution, while others diverge much later. Based on these ribosomal RNA data, Protoctista should be regarded as a collection of independent evolutionary lineages. Because the evolutionary distance between the different groups of Protoctista is, in several cases, larger than the evolutionary distance between plants, fungi and animals, the classification of eukaryotes into four kingdoms seems to be artificial and may not reflect true evolutionary relationships. Generally, eukaryotes are considered to be a relatively recently diverged lineage. Based on ribosomal RNA, however, they seem to be as old as the prokaryote lineages one distinguishes nowadays, namely eubacteria and archaebacteria.

The database on small ribosomal subunit RNA structure contained 1804 nucleotide sequences on April 23, 1993. This number comprises 365 eukaryotic, 65 archaeal, 1260 bacterial, 30 plastidial, and 84 mitochondrial sequences. These are stored in the form of an alignment in order to facilitate the use of the database as input for comparative studies on higher-order structure and for reconstruction of phylogenetic trees. The elements of the postulated secondary structure for each molecule are indicated by special symbols. The database is available on-line directly from the authors by ftp and can also be obtained from the EMBL nucleotide sequence library by electronic mail, ftp, and on CD ROM disk.

Autism is a neurodevelopmental disorder characterized by impaired social reciprocity, impaired communication and stereotypical behaviors. Despite strong evidence for a genetic basis, few susceptibility genes have been identified. Here, we describe the positional cloning of SCAMP5, CLIC4 and PPCDC as candidate genes for autism, starting from a person with idiopathic, sporadic autism carrying a de novo chromosomal translocation. One of these genes, SCAMP5 is silenced on the derivative chromosome, and encodes a brain-enriched protein involved in membrane trafficking, similar to the previously identified candidate genes NBEA and AMISYN. Gene silencing of Nbea, Amisyn and Scamp5 in mouse β-TC3 cells resulted in a 2-fold increase in stimulated secretion of large dense-core vesicles (LDCVs), while overexpression suppressed secretion. Moreover, ultrastructural analysis of blood platelets from the patients with haploinsufficieny of one of the three candidate genes, showed morphological abnormalities of dense-core granules, which closely resemble LDCVs. Taken together, this study shows that in three independent patients with autism three different negative regulators of LDCV secretion are affected, respectively, suggesting that in at least a subgroup of patients the regulation of neuronal vesicle trafficking may be involved in the pathogenesis of autism.

We evaluated multiplex PCR amplification as a front-end for high-throughput sequencing, to widen the applicability of massive parallel sequencers for the detailed analysis of complex genomes. Using multiplex PCR reactions, we sequenced the complete coding regions of seven genes implicated in peripheral neuropathies in 40 individuals on a GS-FLX genome sequencer (Roche). The resulting dataset showed highly specific and uniform amplification. Comparison of the GS-FLX sequencing data with the dataset generated by Sanger sequencing confirmed the detection of all variants present and proved the sensitivity of the method for mutation detection. In addition, we showed that we could exploit the multiplexed PCR amplicons to determine individual copy number variation (CNV), increasing the spectrum of detected variations to both genetic and genomic variants. We conclude that our straightforward procedure substantially expands the applicability of the massive parallel sequencers for sequencing projects of a moderate number of amplicons (50-500) with typical applications in resequencing exons in positional or functional candidate regions and molecular genetic diagnostics.

Background: We identified erm(A)-harbouring Streptococcus pyogenes that expressed three variant phenotypes: (1) low-level resistance to erythromycin (MICs 14 mg/L) but high azithromycin MICs in absolute terms (1664 mg/L; n = 6); (2) same as (1) but with a high clindamycin MIC (256 mg/L; n = 1); and (3) high-level constitutive MLS (cMLS) resistance (n = 1). Here we analysed the genetic basis of these novel phenotypes. Methods: The presence of erm(A) and the absence of macrolide/lincosamide resistance genes erm(B), mef and cfr were confirmed by PCR. erm(A), 23S rRNA, L4 and L22 genes were sequenced. Mutant erm(A) genes were cloned and electrotransformed into the macrolide-susceptible Escherichia coli AG100A. Clonality was determined by emm typing and PFGE. Effects of the identified mutations on free energy changes (G) and putative configurations of the leader sequence were studied in silico. Results: Point mutations (G98A, A137C, C140T and G205A) were observed in the erm(A) regulatory region of all eight erm(A)-harbouring S. pyogenes. Five and two isolates belonged to emm77 and emm89 clones, respectively, and one isolate was an emm1. E. coli transformed with mutant erm(A) harbouring G98A, A137C or C140T mutations (phenotypes 1 and 2) did not express high-level azithromycin or clindamycin resistance. However, cMLS resistance was clearly observed in transformants with erm(A) harbouring both A137C and G205A mutations (phenotype 3). In silico analysis showed that G was minor except for the G205A mutation. Secondary structure predictions further showed that the A137C and G205A mutations together abolished the hairpin sequestering the ribosome-binding and initiation sites of the erm(A) gene, explaining the cMLS phenotype 3. Conclusions: We report point mutations in the erm(A) regulatory region leading to constitutive methylase expression and the presence of additional, as yet unidentified mechanisms mediating high-level azithromycin and clindamycin resistance in erm(A)-harbouring S. pyogenes.

Context Neuregulin 1 (NRG1), a growth factor involved in neurodevelopment, myelination, neurotransmitter receptor expression, and synaptic plasticity, first joined the list of candidate genes for schizophrenia when a 7-marker haplotype at the 5' end of the gene (HapICE) was shown to be associated with the disorder in the Icelandic population. Since then, more genetic and functional evidence has emerged, which supports a role for NRG1 in the development of schizophrenia. Objective To determine the contribution of NRG1 to susceptibility for schizophrenia in a northern Swedish isolated population. Design Detailed linkage disequilibrium (LD)based patient-control association study. This is the first study to type and analyze the 7 HapICE markers and a set of 32 HapMap tagging single-nucleotide polymorphisms (SNPs) that represents variants with a minor allele frequency of at least 1% and fully characterizes the LD structure of the 5' part of NRG1. Setting Outpatient and inpatient hospitals. Participants A total of 486 unrelated patients with schizophrenia and 514 unrelated control individuals recruited from a northern Swedish isolated population. Main Outcome Measures Association between markers and disease. Results Analysis of the HapICE markers showed the association of a 7-marker and 2-microsatellite haplotype, different from the haplotypes associated in the Icelandic population and overrepresented in northern Swedish control individuals. Subsequently, a more detailed analysis that included all 37 genotyped SNPs was performed by investigating haplotypic association, dependent and independent of LD block structure. We found significant association with 5 SNPs located in the second intron of NRG1 (.007 P .04). Also, 2-, 3-, and 4-SNP windows that comprise these SNPs were associated (P < 3 x 104). One protective haplotype (0% vs 1.8%; P

The same high-throughput techniques used to make genomic sequences generally available, are also useful in mapping the genetic differences between individuals. Resequencing of a genomic region in a set of individuals is considered the golden standard for the discovery of sequence variants. However, with the available high-throughput sequencing technology data analysis has become the rate-limiting step in data management and analysis of large resequencing projects. To solve this issue we developed a software package novoSNP that conscientiously discovers single nucleotide polymorphisms and insertion-deletion polymorphisms in sequence trace files in a fast, reliable and user friendly way. Furthermore, it can also be used to create databases containing annotated reference sequences, add and align trace data, keep track of validation status of variants, annotate variants, and produce reports on validated variants and genotypes. novoSNP is available from http://www.molgen.ua.ac.be/bioinfo/novosnp. There are versions for MS Windows as well as Linux.

In this omics era, researchers in biosciences need more than ever user-friendly, fast, and straightforward computational tools for high-throughput research. In this chapter, we present SNPbox and explain the general primer design strategy. We also show how the four modules, Exon, Single-Nucleotide Polymorphism (SNP), Saturation, and Exon + Saturation, exactly apply the primer design strategy, give clear guidance for users of the Web interface at http://www.SNPbox.org, and explain how pre-designed primers for Ensembl genes can be visualized and retrieved.

The same high-throughput techniques used to make genomic sequences generally available, are also useful in mapping the genetic differences between individuals. Resequencing of a genomic region in a set of individuals is considered the golden standard for the discovery of sequence variants. However, with the available high-throughput sequencing technology data analysis has become the rate-limiting step in data management and analysis of large resequencing projects. To solve this issue we developed a software package novoSNP that conscientiously discovers single nucleotide polymorphisms and insertion-deletion polymorphisms in sequence trace files in a fast, reliable and user friendly way. Furthermore, it can also be used to create databases containing annotated reference sequences, add and align trace data, keep track of validation status of variants, annotate variants, and produce reports on validated variants and genotypes. novoSNP is available from http://www.molgen.ua.ac.be/bioinfo/novosnp. There are versions for MS Windows as well as Linux.