Mapping neurodevelopment with sleep macro- and micro-architecture across multiple pediatric populations

Profiles of sleep duration and timing and corresponding electroencephalographic activity reflect brain changes that support cognitive and behavioral maturation and may provide practical markers for tracking typical and atypical neurodevelopment. To build and evaluate a sleep-based, quantitative metric of brain maturation, we used whole-night polysomnography data, initially from two large National Sleep Research Resource samples, spanning childhood and adolescence (total N = 4,013, aged 2.5 to 17.5 years): the Childhood Adenotonsillectomy Trial (CHAT), a research study of children with snoring without neurodevelopmental delay, and Nationwide Children's Hospital (NCH) Sleep Databank, a pediatric sleep clinic cohort. Among children without neurodevelopmental disorders (NDD), sleep metrics derived from the electroencephalogram (EEG) displayed robust age-related changes consistently across datasets. During non-rapid eye movement (NREM) sleep, spindles and slow oscillations further exhibited characteristic developmental patterns, with respect to their rate of occurrence, temporal coupling and morphology. Based on these metrics in NCH, we constructed a model to predict an individual's chronological age. The model performed with high accuracy (r = 0.93 in the held-out NCH sample and r = 0.85 in a second independent replication sample - the Pediatric Adenotonsillectomy Trial for Snoring (PATS)). EEG-based age predictions reflected clinically meaningful neurodevelopmental differences; for example, children with NDD showed greater variability in predicted age, and children with Down syndrome or intellectual disability had significantly younger brain age predictions (respectively, 2.1 and 0.8 years less than their chronological age) compared to age-matched non-NDD children. Overall, our results indicate that sleep architectureoffers a sensitive window for characterizing brain maturation, suggesting the potential for scalable, objective sleep-based biomarkers to measure neurodevelopment.

O28: M6A DEMETHYLASE FTO A POTENTIAL TARGET IN BRAIN METASTATIC BREAST CANCER

Introduction

Brain metastasis (BrM) occurs in 10-30% of patients with advanced breast cancer (BC). BrM is increasing in incidence and confers a poor prognosis. We aimed to investigate the contribution of global epi-transcriptomic alterations in N6-methyladenosine (m6A) RNA-methylation as a therapeutic target in brain metastatic breast cancer.

Method

In preliminary studies we have demonstrated m6A demethylase – FTO as the main contributor to the progression of ER+ breast cancer. Furthermore an association between FTO and reduced disease-free-survival (n=870, p=0.018) was observed. Here we conducted an epigenetic inhibitor screen using two therapeutic agents, ethyl-ester-meclofenamic acid (MA2) and FB23-2 on matched 2D cell line, 3D organoid cultures and patient-derived xenografts (PDX) explant models of brain metastasis.

Result

Upon integration of mapped global RNA methylation landscape with matched proteomic analysis, we observed genome-wide RNA hypo-methylation of key pluripotency genes, including SOX2 and KLF4, as key players underlying tumour progression to the brain.  Genetic and pharmacological inhibition of FTO in novel ex vivo models of BrM significantly reduced protein expression levels of KLF4 and SOX2. Moreover, pharmacological inhibition of FTO with MA2 and FB23-2, inhibited cell proliferation in endocrine-resistant BC and patient BrM cells. We translate our findings to the clinic by demonstrating the efficacy of anti-FTO therapies in several unique PDX and 3D organoid BrM models.

Conclusion

Our results reveal epi-transcriptional remodelling events as a key mechanism in BrM. This study establishes an early role for targeting RNA methylation in the management of disease progression and presents FTO as a potential therapeutic target in BrM.

Take-home message

This study establishes an early role for targeting RNA methylation in the management of disease progression and presents FTO as a potential therapeutic target in brain metastatic breast cancer.

O12: IHC ANALYSIS OF RESIDUAL DISEASE POST NEOADJUVANT TRASTUZUMAB FOR EARLY STAGE BREAST CANCER REVEALS ER/HER2 CROSSTALK THROUGH INCREASED ER SIGNALLING

Introduction

Therapeutic pressure functionally affects oncogenes and related signalling pathways through dynamic alterations in transcriptional and epigenetic alterations. Altered receptor status occurs throughout tumour progression and may be influenced by adjuvant and neoadjuvant therapies. Recurrent transcriptional remodelling events have been described in the progression of primary breast cancer to metastasis, including increased tyrosine kinase signalling, specifically Her2, and loss of ESR1 gene expression. We hypothesise that in the setting of tyrosine kinase inhibition, an increase in estrogen receptor (ER) signalling is observed.

Method

A database of patients recruited to ICORG trial 07/09 was queried to identify patients with histologically confirmed, Her2-overexpressing or Her2 amplified, nonmetastatic, invasive breast cancer who received neoadjuvant trastuzumab, alone or in combination with neoadjuvant systemic chemotherapy. Clinicopathological characteristics recorded include age at diagnosis, clinical stage, receptor status and percentage positivity, and pathological complete response.

Result

A total of 55 patients identified on ICORG trial 09/07 received neoadjuvant trastuzumab. Of these, 27 achieved a complete pathological response (49%; n=27/55). In those with residual disease, a gain in mean ER staining percentage positivity was observed in the residual disease compared to diagnostic biopsy staining (59.22 vs 45.11; p=0.03). A corresponding loss in Her2 percentage staining positivity was also observed (p=0.006).

Conclusion

An inverse correlation was observed between loss of Her2 positivity and percentage gain in ER staining in patients with residual disease following treatment with neoadjuvant trastuzumab. Further study is needed to elucidate the regulatory mechanism of ER/Her2 crosstalk, which may be epigenetically regulated through DNA methylation.

Take-home message

ER/Her2 crosstalk can be demonstrated clinically in IHC analysis of patients with residual disease post neoadjuvant trastuzumab. Tyrosine kinase inhibition in the form of neoadjuvant trastuzumab results in loss of Her2 signalling and corresponding gain in ER signalling.

Determining the composition of the vacuum-liquid interface in ionic-liquid mixtures

The vacuum-liquid interfaces of a number of ionic-liquid mixtures have been investigated using the combination of reactive-atom scattering with laser-induced fluorescence detection (RAS-LIF), selected surface tension measurements, and molecular dynamics (MD) simulations. The mixtures are based on the widespread 1-alkyl-3-methylimidazolium ([C_nmim]⁺) cation, including mixed cations which differ in chain length or chemical functionality with a common anion; and different anions for a common cation. RAS-LIF results imply that the surface compositions exhibit a general form of non-stoichiometric behaviour that mimics the well-known Henry's and Raoult's laws at low and high mole fraction, respectively. The extended Langmuir model provides a moderately good single-parameter fit, but higher-order terms are required for an accurate description. The quantitative relationship between RAS-LIF and surface tension, which probes the surface composition only indirectly, is explored for mixtures of [C₂mim]⁺ and [C₁₂mim]⁺ with a common bis(trifluoromethylsulfonyl)imide ([NTf₂]^-) anion. Extended Langmuir model fits to surface tension data are broadly consistent with those to RAS-LIF; however, several other common approaches to extracting surface compositions from measured surface tensions result in much larger discrepancies. MD simulations suggest that RAS-LIF faithfully reports on the alkyl-chain exposure at the surface, which is only subtly modified by composition-dependent structural reorganisation.

Characterizing sleep spindles in 11,630 individuals from the National Sleep Research Resource

Sleep spindles are characteristic electroencephalogram (EEG) signatures of stage 2 non-rapid eye movement sleep. Implicated in sleep regulation and cognitive functioning, spindles may represent heritable biomarkers of neuropsychiatric disease. Here we characterize spindles in 11,630 individuals aged 4 to 97 years, as a prelude to future genetic studies. Spindle properties are highly reliable but exhibit distinct developmental trajectories. Across the night, we observe complex patterns of age- and frequency-dependent dynamics, including signatures of circadian modulation. We identify previously unappreciated correlates of spindle activity, including confounding by body mass index mediated by cardiac interference in the EEG. After taking account of these confounds, genetic factors significantly contribute to spindle and spectral sleep traits. Finally, we consider topographical differences and critical measurement issues. Taken together, our findings will lead to an increased understanding of the genetic architecture of sleep spindles and their relation to behavioural and health outcomes, including neuropsychiatric disorders.

Sleep patterns vary and are associated with health and disease. Here Purcell et al characterize sleep spindle activity in 11,630 individuals and describe age-related changes, genetic influences, and possible confounding effects, serving as a resource for further understanding the physiology of sleep.

Evidence for genetic heterogeneity between clinical subtypes of bipolar disorder

We performed a genome-wide association study of 6447 bipolar disorder (BD) cases and 12 639 controls from the International Cohort Collection for Bipolar Disorder (ICCBD). Meta-analysis was performed with prior results from the Psychiatric Genomics Consortium Bipolar Disorder Working Group for a combined sample of 13 902 cases and 19 279 controls. We identified eight genome-wide significant, associated regions, including a novel associated region on chromosome 10 (rs10884920; P=3.28 × 10-8) that includes the brain-enriched cytoskeleton protein adducin 3 (ADD3), a non-coding RNA, and a neuropeptide-specific aminopeptidase P (XPNPEP1). Our large sample size allowed us to test the heritability and genetic correlation of BD subtypes and investigate their genetic overlap with schizophrenia and major depressive disorder. We found a significant difference in heritability of the two most common forms of BD (BD I SNP-h2=0.35; BD II SNP-h2=0.25; P=0.02). The genetic correlation between BD I and BD II was 0.78, whereas the genetic correlation was 0.97 when BD cohorts containing both types were compared. In addition, we demonstrated a significantly greater load of polygenic risk alleles for schizophrenia and BD in patients with BD I compared with patients with BD II, and a greater load of schizophrenia risk alleles in patients with the bipolar type of schizoaffective disorder compared with patients with either BD I or BD II. These results point to a partial difference in the genetic architecture of BD subtypes as currently defined.

Fenestrated endografts: are they the solution for visceral and aortic neck issues?

Many patients with short neck or no neck juxtarenal abdominal aortic aneurysms are not candidates for open surgical repair. Current treatment options for such patients include fenestrated endograft repair, placement of chimneys and snorkels (parallel grafts) or use of physician modified endografts. The purpose of this review is to examine the reported literature on the use of fenestrated aortic endografts for juxtarenal aortic aneurysms. A systematic review of the literature, to include clinical trials, case series, and meta-analyses was performed to report the outcomes of the use of fenestrated endovascular repair. The early and midterm results of fenestrated endografting is quite promising. As expected with real world use of the device, many patients do not meet the inclusion criteria of the initial pivotal clinical trials. As such, the results are not as good with respect to morbidity, re-intervention, and device related problems. However, despite such issues, in this difficult to treat population the initial and mid-term results as outlined below are quite acceptable. Fenestrated endografts will continue to gain acceptance and will become the treatment of choice for juxtarenal abdominal aortic aneurysms in the future.

Copy number variation in schizophrenia in Sweden

Schizophrenia (SCZ) is a highly heritable neuropsychiatric disorder of complex genetic etiology. Previous genome-wide surveys have revealed a greater burden of large, rare copy number variations (CNVs) in SCZ cases and identified multiple rare recurrent CNVs that increase risk of SCZ although with incomplete penetrance and pleiotropic effects. Identification of additional recurrent CNVs and biological pathways enriched for SCZ CNVs requires greater sample sizes. We conducted a genome-wide survey for CNVs associated with SCZ using a Swedish national sample (4719 cases and 5917 controls). High-confidence CNV calls were generated using genotyping array intensity data, and their effect on risk of SCZ was measured. Our data confirm increased burden of large, rare CNVs in SCZ cases as well as significant associations for recurrent 16p11.2 duplications, 22q11.2 deletions and 3q29 deletions. We report a novel association for 17q12 duplications (odds ratio=4.16, P=0.018), previously associated with autism and mental retardation but not SCZ. Intriguingly, gene set association analyses implicate biological pathways previously associated with SCZ through common variation and exome sequencing (calcium channel signaling and binding partners of the fragile X mental retardation protein). We found significantly increased burden of the largest CNVs (>500 kb) in genes present in the postsynaptic density, in genomic regions implicated via SCZ genome-wide association studies and in gene products localized to mitochondria and cytoplasm. Our findings suggest that multiple lines of genomic inquiry--genome-wide screens for CNVs, common variation and exonic variation--are converging on similar sets of pathways and/or genes.

Body imaging

No abstract available.

Genome-wide significant associations in schizophrenia to ITIH3/4, CACNA1C and SDCCAG8, and extensive replication of associations reported by the Schizophrenia PGC

The Schizophrenia Psychiatric Genome-Wide Association Study Consortium (PGC) highlighted 81 single-nucleotide polymorphisms (SNPs) with moderate evidence for association to schizophrenia. After follow-up in independent samples, seven loci attained genome-wide significance (GWS), but multi-locus tests suggested some SNPs that did not do so represented true associations. We tested 78 of the 81 SNPs in 2640 individuals with a clinical diagnosis of schizophrenia attending a clozapine clinic (CLOZUK), 2504 cases with a research diagnosis of bipolar disorder, and 2878 controls. In CLOZUK, we obtained significant replication to the PGC-associated allele for no fewer than 37 (47%) of the SNPs, including many prior GWS major histocompatibility complex (MHC) SNPs as well as 3/6 non-MHC SNPs for which we had data that were reported as GWS by the PGC. After combining the new schizophrenia data with those of the PGC, variants at three loci (ITIH3/4, CACNA1C and SDCCAG8) that had not previously been GWS in schizophrenia attained that level of support. In bipolar disorder, we also obtained significant evidence for association for 21% of the alleles that had been associated with schizophrenia in the PGC. Our study independently confirms association to three loci previously reported to be GWS in schizophrenia, and identifies the first GWS evidence in schizophrenia for a further three loci. Given the number of independent replications and the power of our sample, we estimate 98% (confidence interval (CI) 78-100%) of the original set of 78 SNPs represent true associations. We also provide strong evidence for overlap in genetic risk between schizophrenia and bipolar disorder.

Multi-locus genome-wide association analysis supports the role of glutamatergic synaptic transmission in the etiology of major depressive disorder

Major depressive disorder (MDD) is a common psychiatric illness characterized by low mood and loss of interest in pleasurable activities. Despite years of effort, recent genome-wide association studies (GWAS) have identified few susceptibility variants or genes that are robustly associated with MDD. Standard single-SNP (single nucleotide polymorphism)-based GWAS analysis typically has limited power to deal with the extensive heterogeneity and substantial polygenic contribution of individually weak genetic effects underlying the pathogenesis of MDD. Here, we report an alternative, gene-set-based association analysis of MDD in an effort to identify groups of biologically related genetic variants that are involved in the same molecular function or cellular processes and exhibit a significant level of aggregated association with MDD. In particular, we used a text-mining-based data analysis to prioritize candidate gene sets implicated in MDD and conducted a multi-locus association analysis to look for enriched signals of nominally associated MDD susceptibility loci within each of the gene sets. Our primary analysis is based on the meta-analysis of three large MDD GWAS data sets (total N=4346 cases and 4430 controls). After correction for multiple testing, we found that genes involved in glutamatergic synaptic neurotransmission were significantly associated with MDD (set-based association P=6.9 × 10(-4)). This result is consistent with previous studies that support a role of the glutamatergic system in synaptic plasticity and MDD and support the potential utility of targeting glutamatergic neurotransmission in the treatment of MDD.

Functional gene group analysis identifies synaptic gene groups as risk factor for schizophrenia

Schizophrenia is a highly heritable disorder with a polygenic pattern of inheritance and a population prevalence of ~1%. Previous studies have implicated synaptic dysfunction in schizophrenia. We tested the accumulated association of genetic variants in expert-curated synaptic gene groups with schizophrenia in 4673 cases and 4965 healthy controls, using functional gene group analysis. Identifying groups of genes with similar cellular function rather than genes in isolation may have clinical implications for finding additional drug targets. We found that a group of 1026 synaptic genes was significantly associated with the risk of schizophrenia (P=7.6 × 10(-11)) and more strongly associated than 100 randomly drawn, matched control groups of genetic variants (P<0.01). Subsequent analysis of synaptic subgroups suggested that the strongest association signals are derived from three synaptic gene groups: intracellular signal transduction (P=2.0 × 10(-4)), excitability (P=9.0 × 10(-4)) and cell adhesion and trans-synaptic signaling (P=2.4 × 10(-3)). These results are consistent with a role of synaptic dysfunction in schizophrenia and imply that impaired intracellular signal transduction in synapses, synaptic excitability and cell adhesion and trans-synaptic signaling play a role in the pathology of schizophrenia.

Genome-wide association study in a Swedish population yields support for greater CNV and MHC involvement in schizophrenia compared with bipolar disorder

Schizophrenia (SCZ) and bipolar disorder (BD) are highly heritable psychiatric disorders with overlapping susceptibility loci and symptomatology. We conducted a genome-wide association study (GWAS) of these disorders in a large Swedish sample. We report a new and independent case-control analysis of 1507 SCZ cases, 836 BD cases and 2093 controls. No single-nucleotide polymorphisms (SNPs) achieved significance in these new samples; however, combining new and previously reported SCZ samples (2111 SCZ and 2535 controls) revealed a genome-wide significant association in the major histocompatibility complex (MHC) region (rs886424, P=4.54 × 10(-8)). Imputation using multiple reference panels and meta-analysis with the Psychiatric Genomics Consortium SCZ results underscored the broad, significant association in the MHC region in the full SCZ sample. We evaluated the role of copy number variants (CNVs) in these subjects. As in prior reports, deletions were enriched in SCZ, but not BD cases compared with controls. Singleton deletions were more frequent in both case groups compared with controls (SCZ: P=0.003, BD: P=0.013), whereas the largest CNVs (>500 kb) were significantly enriched only in SCZ cases (P=0.0035). Two CNVs with previously reported SCZ associations were also overrepresented in this SCZ sample: 16p11.2 duplications (P=0.0035) and 22q11 deletions (P=0.03). These results reinforce prior reports of significant MHC and CNV associations in SCZ, but not BD.

GENESiS: creating a composite index of the vulnerability to anxiety and depression in a community-based sample of siblings

There is considerable evidence for a unitary and dimensional view of the genetic vulnerability to symptoms of anxiety and depression. The GENESiS (Genetic Environmental–Nature of Emotional States in Siblings) Study aims to use a multivariate approach to detect genetic loci that contribute to individual differences in this vulnerability dimension. The study used the UK General Practice Research Framework to generate a community-based sample of siblings. Questionnaire measures of anxiety/depression included the short form of the neuroticism scale from the revised Eysenck Personality Questionnaire (EPQ-N), the General Health Questionnaire (GHQ-12), and the anxious arousal and high positive affect subscales from the Mood and Anxiety Symptoms Questionnaire (MASQ-AA and MASQ-HPA). Genetic model-fitting of 2658 unselected sibships provided evidence for a single common genetic (familial) factor that accounted for a substantial proportion of the genetic variances and covariances of these four measures. Using the parameter estimates of this model, we constructed a composite index of this common genetic factor. This index, which has a sib correlation of 0.22, will be used as a quantitative phenotype in the molecular genetic phase of GENESiS. Twin Research (2000) 3, 316–322.

De novo CNV analysis implicates specific abnormalities of postsynaptic signalling complexes in the pathogenesis of schizophrenia

A small number of rare, recurrent genomic copy number variants (CNVs) are known to substantially increase susceptibility to schizophrenia. As a consequence of the low fecundity in people with schizophrenia and other neurodevelopmental phenotypes to which these CNVs contribute, CNVs with large effects on risk are likely to be rapidly removed from the population by natural selection. Accordingly, such CNVs must frequently occur as recurrent de novo mutations. In a sample of 662 schizophrenia proband-parent trios, we found that rare de novo CNV mutations were significantly more frequent in cases (5.1% all cases, 5.5% family history negative) compared with 2.2% among 2623 controls, confirming the involvement of de novo CNVs in the pathogenesis of schizophrenia. Eight de novo CNVs occurred at four known schizophrenia loci (3q29, 15q11.2, 15q13.3 and 16p11.2). De novo CNVs of known pathogenic significance in other genomic disorders were also observed, including deletion at the TAR (thrombocytopenia absent radius) region on 1q21.1 and duplication at the WBS (Williams-Beuren syndrome) region at 7q11.23. Multiple de novos spanned genes encoding members of the DLG (discs large) family of membrane-associated guanylate kinases (MAGUKs) that are components of the postsynaptic density (PSD). Two de novos also affected EHMT1, a histone methyl transferase known to directly regulate DLG family members. Using a systems biology approach and merging novel CNV and proteomics data sets, systematic analysis of synaptic protein complexes showed that, compared with control CNVs, case de novos were significantly enriched for the PSD proteome (P=1.72 × 10⁻⁶. This was largely explained by enrichment for members of the N-methyl-D-aspartate receptor (NMDAR) (P=4.24 × 10⁻⁶) and neuronal activity-regulated cytoskeleton-associated protein (ARC) (P=3.78 × 10⁻⁸) postsynaptic signalling complexes. In an analysis of 18 492 subjects (7907 cases and 10 585 controls), case CNVs were enriched for members of the NMDAR complex (P=0.0015) but not ARC (P=0.14). Our data indicate that defects in NMDAR postsynaptic signalling and, possibly, ARC complexes, which are known to be important in synaptic plasticity and cognition, play a significant role in the pathogenesis of schizophrenia.

Relationship between diagnosis and intervention in women with inherited bleeding disorders and menorrhagia

Menorrhagia is the most common bleeding manifestation in women with inherited bleeding disorders. There is little known about whether the management of menorrhagia is altered in specific bleeding disorders. Optimizing treatment strategies for each specific diagnosis may improve quality of life in these women. This work aimed to look for a potential relationship between the specific diagnosis of an inherited bleeding disorder and the intervention required to control the menorrhagia. A retrospective chart review was performed for all women seen in the Kingston Women and Bleeding Disorders Clinic. Patients were categorized by diagnosis into two groups: Haemophilia carriers and all others. Treatment options were grouped into two categories: Medical or gynecological/surgical. Overall, 85.7% of haemophilia carriers required gynaecological surgical management, whereas only 31.4% of patients with all other diagnoses required gynaecological/surgical management (P = 0.012, Fisher's exact test). Therefore, carriers of Haemophilia were more likely to have a better outcome in treating their menorrhagia with gynaecological or surgical management compared with medical management. This information may 1 day help to guide treatment choice for menorrhagia in women with bleeding disorders.

Polygenic dissection of the bipolar phenotype

BACKGROUND

Recent data provide strong support for a substantial common polygenic contribution (i.e. many alleles each of small effect) to genetic susceptibility for schizophrenia and overlapping susceptibility for bipolar disorder.

AIMS

To test hypotheses about the relationship between schizophrenia and psychotic types of bipolar disorder.

METHOD

Using a polygenic score analysis to test whether schizophrenia polygenic risk alleles, en masse, significantly discriminate between individuals with bipolar disorder with and without psychotic features. The primary sample included 1829 participants with bipolar disorder and the replication sample comprised 506 people with bipolar disorder.

RESULTS

The subset of participants with Research Diagnostic Criteria schizoaffective bipolar disorder (n = 277) were significantly discriminated from the remaining participants with bipolar disorder (n = 1552) in both the primary (P = 0.00059) and the replication data-sets (P = 0.0070). In contrast, those with psychotic bipolar disorder as a whole were not significantly different from those with non-psychotic bipolar disorder in either data-set.

CONCLUSIONS

Genetic susceptibility influences at least two major domains of psychopathological variation in the schizophrenia-bipolar disorder clinical spectrum: one that relates to expression of a 'bipolar disorder-like' phenotype and one that is associated with expression of 'schizophrenia-like' psychotic symptoms.

Tailoring the optical dipole force for molecules by field-induced alignment

We report on the ability to tailor the optical dipole force for molecules by tuning their effective polarizability with strong field alignment using polarized fields. We have measured a difference of 20% in the dipole force on cold CS2 molecules when changing from linear to near-circular polarization using peak field intensities of 5.7x10(11) W cm(-2). A variation in the focal length with laser polarization of a molecular-optical lens formed by a single focused laser beam was also measured. This provides a new way of modifying this force for many molecules.

A large-scale international meta-analysis of paraoxonase gene polymorphisms in sporadic ALS

BACKGROUND

Six candidate gene studies report a genetic association of DNA variants within the paraoxonase locus with sporadic amyotrophic lateral sclerosis (ALS). However, several other large studies, including five genome-wide association studies, have not duplicated this finding.

METHODS

We conducted a meta-analysis of 10 published studies and one unpublished study of the paraoxonase locus, encompassing 4,037 ALS cases and 4,609 controls, including genome-wide association data from 2,018 ALS cases and 2,425 controls.

RESULTS

The combined fixed effects odds ratio (OR) for rs662 (PON1 Q192R) was 1.09 (95% confidence interval [CI], 1.02-1.16, p = 0.01); the genotypic OR for RR homozygotes at Q192R was 1.25 (95% CI, 1.07-1.45, p = 0.0004); the combined OR for rs854560 (PON1 L55M) was 0.97 (95% CI, 0.86-1.10, p = 0.62); the OR for rs10487132 (PON2) was 1.08 (95% CI, 0.92-1.27, p = 0.35). Although the rs662 polymorphism reached a nominal level of significance, no polymorphism was significant after multiple testing correction. In the subanalysis of samples with genome-wide data from which population outliers were removed, rs662 had an OR of 1.06 (95% CI, 0.97-1.16, p = 0.22).

CONCLUSIONS

In contrast to previous positive smaller studies, our genetic meta-analysis showed no significant association of amyotrophic lateral sclerosis (ALS) with the PON locus. This is the largest meta-analysis of a candidate gene in ALS to date and the first ALS meta-analysis to include data from whole genome association studies. The findings reinforce the need for much larger and more collaborative investigations of the genetic determinants of ALS.

Application of genome-wide SNP data for uncovering pairwise relationships and quantitative trait loci

The genetic analysis of quantitative traits in humans is changing as a result of the availability of whole-genome SNP data. Heritability analysis can make use of actual genetic sharing between pairs of individuals estimated from the genotype data, rather than the expected genetic sharing implied by their family relationship. This could provide more accurate heritability estimates and help to overcome the equal environment assumption. Quantitative trait locus (QTL) linkage mapping can make use of local genetic sharing inferred from very dense local genotype data from pedigree members or individuals not previously known to be related. This approach may be particularly suited for detecting loci that contain rare variants with major effect on the phenotype. Finally, whole-genome SNP data can be used to measure the genetic similarity between individuals to provide matched sets for association studies, in order to avoid spurious association from population stratification.

Whole-genome association study of bipolar disorder

We performed a genome-wide association scan in 1461 patients with bipolar (BP) 1 disorder, 2008 controls drawn from the Systematic Treatment Enhancement Program for Bipolar Disorder and the University College London sample collections with successful genotyping for 372,193 single nucleotide polymorphisms (SNPs). Our strongest single SNP results are found in myosin5B (MYO5B; P=1.66 x 10(-7)) and tetraspanin-8 (TSPAN8; P=6.11 x 10(-7)). Haplotype analysis further supported single SNP results highlighting MYO5B, TSPAN8 and the epidermal growth factor receptor (MYO5B; P=2.04 x 10(-8), TSPAN8; P=7.57 x 10(-7) and EGFR; P=8.36 x 10(-8)). For replication, we genotyped 304 SNPs in family-based NIMH samples (n=409 trios) and University of Edinburgh case-control samples (n=365 cases, 351 controls) that did not provide independent replication after correction for multiple testing. A comparison of our strongest associations with the genome-wide scan of 1868 patients with BP disorder and 2938 controls who completed the scan as part of the Wellcome Trust Case-Control Consortium indicates concordant signals for SNPs within the voltage-dependent calcium channel, L-type, alpha 1C subunit (CACNA1C) gene. Given the heritability of BP disorder, the lack of agreement between studies emphasizes that susceptibility alleles are likely to be modest in effect size and require even larger samples for detection.

Further evidence of association between two NET single-nucleotide polymorphisms with ADHD

The norepinephrine transporter (NET) gene is an attractive candidate gene for attention-deficit hyperactivity disorder (ADHD). Noradrenergic systems are critical to higher brain functions such as attention and executive function, which are defective in ADHD. The clinical efficacy of medications that target NET also supports its role in the etiology of ADHD. Here, we have applied a dense mapping strategy to capture all genetic variations within the NET gene in a large number of ADHD families (474 trios). As a result, we found association of the same alleles from two single-nucleotide polymorphisms (rs3785143 and rs11568324) previously identified in another large-scale ADHD genetic study (International Multisite ADHD Geneproject). Furthermore, the effect sizes were consistent across both studies. This is the first time that identical alleles of NET from different studies were implicated, and thus our report provides further evidence that the NET gene is involved in the etiology of ADHD.

Investigation of variation in SNAP-25 and ADHD and relationship to co-morbid major depressive disorder

Synaptosomal-associated protein of 25 kDa (SNAP-25), a protein involved in presynaptic neurotransmitter release, is a candidate gene for attention deficit/hyperactivity disorder (ADHD). Previous investigators have reported association initially with two single nucleotide polymorphisms (SNPs) (rs3746544, rs1051312) and their associated haplotypes. Subsequently, additional SNPs across the region were also reported to be associated with ADHD. We attempted to replicate these observations in a sample of 229 families with ADHD offspring by genotyping 61 SNPs spanning the region containing SNAP-25. A single SNP (rs3787283) which is in strong linkage disequilibrium (LD) with rs3746544 and rs1051312 (D' = 0.89-0.94) resulted in a nominally significant association (P = 0.002). When we pooled our data with those from prior studies, results were modestly significant for rs3746544 (P = 0.048) and rs6077690 (P = 0.031). As an attempt to determine if specific ADHD-related phenotypes may be more relevant to SNAP-25 than the categorical diagnosis, we carried out exploratory subgroup analysis in our ADHD sample according to co-morbid status. We found the strongest association result in the ADHD patients with co-morbid major depressive disorder (MDD). Six SNPs were nominally associated with the ADHD and co-morbid MDD cases (P = 0.012-0.045). Furthermore, a haplotype block located 11 kb 3' of the gene showed positive evidence for association with this phenotype (global P = 0.013). In conclusion, we report some evidence supporting the association of previously implicated SNPs (rs3746544, rs1051312) of SNAP-25 to ADHD. We further suggest that co-morbidity with MDD may enhance detection of the association between SNAP-25 and ADHD.

359 ICSI AND ACTIVATION OF OOCYTES RECOVERED FROM TRANSITIONAL AND CYCLING MARES

Ovarian follicular development in mares during the transitional period before the breeding season leads to an accumulation of antral follicles of various sizes. The quality of oocytes at this stage may be compromized until the first seasonal ovulation. In this study, we evaluated the developmental competence of oocytes recovered from transitional and cyclic mares, and the effect of zygote activation after intracytoplasmic sperm injection (ICSI). A 2 × 2 × 2 factorial experiment consisting of oocytes from transitional and cyclic mares, two follicle sizes (10 to 20 and 20+ mm), and two treatments (control and activated) was conducted. Follicular oocytes of 14 mares were aspirated in March and April (transitional) and May to July (cyclic) five times per each period at 10-day intervals, without use of hCG. Oocytes aspirated from mares were matured in vitro in a defined medium similar to SOF plus FSH, LH, epidermal growth factor (EGF), insulin-like growth factor (IGF), estradiol (E2), prostaglandin (P4) and 10% FCS, for 30 ± 1 h under 5% CO2 in air at 38.5°C; oocytes with a first polar body were used for ICSI. Motile sperm from frozen-thawed semen were used for sperm injection with a piezo-driven pipet. For activation after ICSI, presumptive zygotes were cultured in G1.3 containing 0.02 µM phorbol 12-myristate 13-acetate (PMA) for 2 h, and then in 2 mM 6-dimethylaminopurine (6-DMAP) for 3 h under 6% CO2 in air at 38.5°C. Zygotes were cultured in 50 µL drops of DMEM/F12 containing 10% FCS for 9 days at 38.5°C in 5% CO2/5% O2/90% N2. Medium was replaced every 3 days. Cleavage and blastocyst rates were calculated based on non-degenerating injected oocytes. Data were analyzed by Fisher's exact test. A total of 115 and 78 oocytes were recovered from cyclic and transitional mares. Average maturation rates to MII in the respective groups were 76.5 and 65.4%, respectively (P < 0.07), and those of 10 to 20 and 20+ mm follicle groups were 70.6 and 80.0%, respectively (P > 0.05). The average cleavage rate in cyclic mares was higher than in transitional mares, and that of the activated group averaged over follicle sizes was higher than that of controls (P < 0.05; Table 1); those of 10 to 20 and 20+ mm follicle groups were not different (P < 0.05; Table 1). Blastocyst rates per oocyte within main effects were not different (P < 0.05; Table 1). Oocytes from transitional mares had lower cleavage rates than those of cyclic mares, but blastocyst development was similar. Activation of zygotes clearly improved cleavage rates of in vivo-derived immature equine oocytes after ICSI. Table 1. Main effect means of responses after ICSI