William Hennah

Comorbidity is high in neurodevelopmental disorders. Therefore, neurodevelopmental phenotypes commonly present a variety of symptoms implicating multiple disorders. Overlapping symptom combinations make diagnostics and treatment difficult, and the interplay of disorder symptoms and traits in these complex phenotypes is yet to be fully understood. We investigated the connections among different traits related to autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), alongside psychiatric internalizing and externalizing symptoms in these disorders. We used a clinically detailed cohort of 30 children with complex phenotypic presentations (24 boys and six girls; mean age: 6.8 years). We applied correlation network techniques to analyze data from comprehensive clinical assessments, comprising standardized neuropsychological and clinical tests, parental questionnaires, self-reported family history, birth-related data, and medical diagnoses. Our main result indicated distinct symptom clusters aligning with separate ASD and ADHD diagnoses, even in the complex neurodevelopmental profiles investigated. Additionally, ADHD traits, and internalizing and externalizing psychiatric symptoms formed a consistent pattern, separate from the ASD traits. Furthermore, neurodevelopmental background factors formed distinct associations with the ASD and ADHD clusters. The findings of this study underscore the independent diagnostic utility of ASD and ADHD constructs even in the context of complex neurodevelopmental manifestations and highlight the central role of attention deficits in them.

Neuropathic pain is a common and debilitating symptom with limited treatment options. Genetic studies, which can provide vital evidence for drug development, have identified only 3 genome-wide significant signals for neuropathic pain traits. To address this, we performed the largest genome-wide association study (GWAS) to date of all-cause neuropathic pain and neuropathic pain subtypes. We defined all-cause neuropathic pain and 33 neuropathic pain subtypes using DeepPheWAS software in the UK Biobank, taking advantage of the longitudinal drug prescription data alongside clinical and self-reported records. We performed a GWAS of all-cause neuropathic pain (33,278 cases, 140,134 controls) as our primary analysis and GWASs of neuropathic pain subtypes as secondary analyses. We used 8 variant-to-gene criteria to identify putative causal genes. We identified 7 independent novel genome-wide associations for neuropathic pain phenotypes, which mapped to 22 novel putative causal genes. NCAM1 was the only gene identified from the primary analysis of all-cause neuropathic pain and met the most variant-to-gene criteria (4) of any identified gene. Of the 21 other genes, ASCC1, CHST3, C4A/C4B , and KCNN2 had the most compelling evidence for mechanistic involvement in neuropathic pain. We have performed the largest GWAS to date of all-cause neuropathic pain and more than doubled the number of genome-wide significant associations for neuropathic pain traits, identifying putative causal genes. There is strong evidence for the involvement of NCAM1 in neuropathic pain, which merits for further study for drug development.

Background: Chronic dry cough is a symptom of common lung conditions, can occur as a side-effect of angiotensin-converting enzyme inhibitors (ACEis), or may be unexplained. Despite the substantial health burden presented by chronic dry cough, its biological mechanisms remain unclear. We hypothesised shared genetic architecture between chronic dry cough and ACEi-induced cough and aimed to identify causal genes underlying both phenotypes. Methods: We performed multi-ancestry genome-wide association studies (GWAS) of chronic dry cough and ACEi-induced cough, and a multi-trait GWAS of both phenotypes, utilising data from five cohort studies. Chronic dry cough was defined by questionnaire responses, and ACEi-induced cough by treatment switches or clinical diagnosis in electronic health records. We mapped putative causal genes and performed phenome-wide association studies (PheWAS) of associated variants, and polygenic scores for ACEi-induced cough, to identify pleiotropic effects. Results: We found seven novel genetic association signals reaching p–8 in the multi-trait or single-trait analyses of chronic dry cough and ACEi-induced cough. The novel variants mapped to 10 novel genes, and we mapped an additional three novel genes to known risk variants, many of which implicate neurological functions ( CTNNA1 , KCNA10 , MAPKAP1 , OR4C12 , OR4C13 , SIL1 ). The polygenic-score-based PheWAS highlighted associations with an elevated risk of several clinical conditions including asthma, diabetes and multi-site chronic pain. Conclusion: Our findings provide support for neuronal dysfunction underlying cough hypersensitivity in chronic dry cough and ACEi-induced cough, and identify diseases and traits associated with genetic predisposition to cough that could inform drug target discovery.

Background: Neuropathic pain is a common and debilitating symptom with limited treatment options. Genetic studies, which can provide vital evidence for drug development, have identified only five genome-wide significant signals for neuropathic pain traits. To address this, we performed the largest genome-wide association study (GWAS) to date of all-cause neuropathic pain and neuropathic pain subtypes. Methods: We defined all-cause neuropathic pain and 33 neuropathic pain subtypes using DeepPheWAS software in the UK Biobank, taking advantage of the longitudinal drug prescription data alongside clinical and self-reported records. We performed a GWAS of all-cause neuropathic pain (33,278 cases, 140,134 controls) as our primary analysis and GWASs of neuropathic pain subtypes as secondary analyses. We used eight variant-to-gene criteria to identify putative causal genes. Results: We identified seven independent novel genome-wide associations for neuropathic pain phenotypes which mapped to 22 novel putative causal genes. NCAM1 was the only gene identified from the primary analysis of all-cause neuropathic pain and met the most variant-to-gene criteria (four) of any identified gene. Of the 21 other genes, ASCC1, CHST3, C4A/C4B and KCNN2 had the most compelling evidence for mechanistic involvement in neuropathic pain. Discussion: We have performed the largest GWAS to date of all-cause neuropathic pain and more than doubled the number of genome-wide significant associations for neuropathic pain traits, identifying putative causal genes. There is strong evidence for the involvement of NCAM1 in neuropathic pain which merits for further study for drug development.

Summary: DeepPheWAS is an R package for phenome wide association studies that creates clinically-curated composite phenotypes, and integrates quantitative phenotypes from primary care data, longitudinal trajectories of quantitative measures, disease progression, and drug response phenotypes. Tools are provided for efficient analysis of association with any genetic input, under any genetic model, with optional sex-stratified analysis, and for developing novel phenotypes. Availability and Implementation: The DeepPheWAS R package is freely available under GNU general public licence v3.0 from at https://github.com/Richard-Packer/DeepPheWAS . Contact: richard.packer@leicester.ac.uk Supplementary information: Supplementary methods and results are available at Bioinformatics online.

Through copy number variations, the 16p13.11 locus has been consistently linked to mental disorders. This locus contains the NDE1 gene, which also encodes microRNA-484. Both of them have been highlighted to play a role in the etiology of mental illness. A 4-SNP haplotype spanning this locus has been shown to associate with schizophrenia in Finnish females. Here we set out to identify any functional variations implicated by this haplotype. We used a sequencing and genotyping study design to identify variations of interest in a Finnish familial cohort ascertained for schizophrenia. We identified 295 variants through sequencing, none of which were located directly within microRNA-484. Two variants were observed to associate with schizophrenia in a sex-dependent manner (females only) in the whole schizophrenia familial cohort (rs2242549 P = .00044; OR = 1.20, 95% CI 1.03–1.40; rs881803 P = .00021; OR = 1.20, 95% CI 1.02–1.40). Both variants were followed up in additional psychiatric cohorts, with neuropsychological traits, and gene expression data, in order to further examine their role. Gene expression data from the familial schizophrenia cohort demonstrated a significant association between rs881803 and 1504 probes (FDR q < 0.05). These were significantly enriched for genes that are predicted miR-484 targets (n = 54; P = .000193), and with probes differentially expressed between the sexes (n = 48; P = .000187). While both SNPs are eQTLs for NDE1, rs881803 is located in a predicted transcription factor binding site. Based on its location and association pattern, we conclude that rs881803 is the prime functional candidate under this locus, affecting the roles of both NDE1 and miR-484 in psychiatric disorders.

We have previously reported a replicable association between variants at the PDE4D gene and familial schizophrenia in a Finnish cohort. In order to identify the potential functional mutations underlying these previous findings, we sequenced 1.5 Mb of the PDE4D genomic locus in 20 families (consisting of 96 individuals and 79 independent chromosomes), followed by two stages of genotyping across 6668 individuals from multiple Finnish cohorts for major mental illnesses. We identified 4570 SNPs across the PDE4D gene, with 380 associated to schizophrenia (p ≤ 0.05). Importantly, two of these variants, rs35278 and rs165940, are located at transcription factor-binding sites, and displayed replicable association in the two-stage enlargement of the familial schizophrenia cohort (combined statistics for rs35278 p = 0.0012; OR = 1.18, 95% CI: 1.06–1.32; and rs165940 p = 0.0016; OR = 1.27, 95% CI: 1.13–1.41). Further analysis using additional cohorts and endophenotypes revealed that rs165940 principally associates within the psychosis (p = 0.025, OR = 1.18, 95% CI: 1.07–1.30) and cognitive domains of major mental illnesses (g-score p = 0.044, β = –0.033). Specifically, the cognitive domains represented verbal learning and memory (p = 0.0091, β = –0.044) and verbal working memory (p = 0.0062, β = −0.036). Moreover, expression data from the GTEx database demonstrated that rs165940 significantly correlates with the mRNA expression levels of PDE4D in the cerebellum (p-value = 0.04; m-value = 0.9), demonstrating a potential functional consequence for this variant. Thus, rs165940 represents the most likely functional variant for major mental illness at the PDE4D locus in the Finnish population, increasing risk broadly to psychotic disorders.

We have previously reported a replicable association between variants at the PDE4D gene and familial schizophrenia in a Finnish cohort. In order to identify the potential functional mutations alluded to by these previous findings, we sequenced the 1.5Mb of the PDE4D genomic locus in 20 families (consisting of 96 individuals, and 79 independent chromosomes), followed by two stages of genotyping across 6,668 individuals from multiple Finnish cohorts for major mental illnesses. We identified 4,570 SNPs across the PDE4D gene, with 380 associated to schizophrenia (p≤0.05). Importantly, two of these variants, rs35278 and rs165940, are located at transcription factor binding sites, and displayed replicable association in the two-stage enlargement of the familial schizophrenia cohort, (combined statistics for rs35278 p=0.0012; OR=1.18, 95% CI 1.06-1.32; and rs165940 p=0.0016; OR=1.27, 95% CI 1.13-1.41). Further analysis using additional cohorts and endophenotypes revealed that rs165940 principally associates within the psychosis (p=0.025, OR=1.18, 95% CI 1.07-1.30) and cognitive domains of major mental illnesses (g-score p=0.044, beta=-0.033). Specifically, the cognitive domains represented verbal learning and memory (p=0.0091, beta=-0.044) and verbal working memory (p=0.0062, beta=-0.036). Moreover, expression data from the GTEx database demonstrated that rs165940 significantly correlates with the mRNA expression levels of PDE4D in the cerebellum (p-value=0.04; m-value=0.9), demonstrating a potential functional consequence for this variant. Thus, rs165940 represents the most likely functional variant for major mental illness at the PDE4D locus in the Finnish population, increasing risk broadly to psychotic disorders.

Whilst the role of the Disrupted-in-Schizophrenia 1 (DISC1) gene in the aetiology of major mental illnesses is debated, the characterization of its function lends it credibility as a candidate. A key aspect of this functional characterization is the determination of the role of common non-synonymous polymorphisms on normal variation within these functions. The common allele (A) of the DISC1 single-nucleotide polymorphism (SNP) rs821616 encodes a serine (ser) at the Ser704Cys polymorphism, and has been shown to increase the phosphorylation of extracellular signal-regulated protein Kinases 1 and 2 (ERK1/2) that stimulate the phosphorylation of tyrosine hydroxylase, the rate-limiting enzyme for dopamine biosynthesis. We therefore set out to test the hypothesis that human ser (A) homozygotes would show elevated dopamine synthesis capacity compared with cysteine (cys) homozygotes and heterozygotes (TT and AT) for rs821616. [¹⁸F]-DOPA positron emission tomography (PET) was used to index striatal dopamine synthesis capacity as the influx rate constant K_i^cer in healthy volunteers DISC1 rs821616 ser homozygotes (N = 46) and healthy volunteers DISC1 rs821616 cys homozygotes and heterozygotes (N = 56), matched for age, gender, ethnicity and using three scanners. We found DISC1 rs821616 ser homozygotes exhibited a significantly higher striatal K_i^cer compared with cys homozygotes and heterozygotes (P = 0.012) explaining 6.4% of the variance (partial η² = 0.064). Our finding is consistent with its previous association with heightened activation of ERK1/2, which stimulates tyrosine hydroxylase activity for dopamine synthesis. This could be a potential mechanism mediating risk for psychosis, lending further credibility to the fact that DISC1 is of functional interest in the aetiology of major mental illness.