Search

South Africa's HIV epidemic has evolved over time in terms of numbers of people living with HIV, access to antiretroviral treatment (ART) and age. These changes have profoundly influenced local cancer patterns. The Johannesburg Cancer Study has, over a period of 22 years (1995-2016), recruited over 20 000 incident black cancer patients who consented to provide answers to a questionnaire and blood samples (serum, DNA). This has presented a unique opportunity to examine the evolving association of HIV with cancer in Africa. We used logistic regression models to explore case-control associations between specific cancers and HIV, using participants with non-infection related cancers as controls. Using data of 20 835 cancer patients with confirmed HIV status, we found the following cancers to be associated with HIV: Kaposi's sarcoma (OR

Although infectious diseases continue to present a major health care problem in Africa, the incidence of cancer is increasing rapidly on the African continent and this merits an increased investment in cancer research in low to medium resource settings. Esophageal squamous cell carcinoma (ESCC) has a high incidence in Eastern and Southern Africa, with late clinical presentation and a very poor prognosis. There is limited research on the molecular pathology of this cancer in Africa, partly as a result of a lack of infrastructure for biobanking and sample processing in many African countries. The aim of this study was to establish a practical and robust workflow to collect, store, and process esophageal cancer samples such that both the tissue architecture and quality of the samples would be preserved and suitable for future genomic research. We developed a workflow that allows storage of fresh biopsy tissue in sterile Eppendorf tubes containing RNAlater, an efficient RNAse inhibitor. We collected 142 ESCC biopsy samples and showed that storage in RNAlater for up to 18 months did not alter tissue morphology, thus allowing histologic assessment by experienced pathologists and determination of tumor content in each biopsied sample. DNA and RNA extracted from tissue samples was assessed for purity, molecular size, and yield. The quantity and quality of nucleic acids obtained were suitable for genomic applications, and whole-exome sequencing of DNA from tumor tissues produced sequence data with a high proportion of both usable reads and correct base calling. We conclude that this workflow may be applicable to a wide range of malignancies for future genomic research in low-resource settings.

Kaposi Sarcoma (KS) is endemic in several countries in Southern and Eastern Africa, relatively rare worldwide but a leading cancer among people living with HIV. KS has always been more common in adult males than females. We assessed the prevalence of known cancer modifying factors (parity, hormonal contraceptive use in females, sex-partners, smoking and alcohol consumption in both sexes), and their relationship to KS, and whether any of these could account for the unequal KS sex ratios. We calculated logistic regression case-control adjusted odds ratios (ORadj), and 95% confidence intervals (95%CI), between KS and each of the modifying factors, using appropriate comparison controls. Controls were cancer types that had no known relationship to exposures of interest (infection or alcohol or smoking or contraceptive use). The majority of the 1275 KS cases were HIV positive (97%), vs. 15.7% in 10,309 controls. The risk of KS among those with HIV was high in males (ORadj=116.70;95%CI=71.35–190.88) and females (ORadj=93.91;95%CI=54.22–162.40). Among controls, the prevalence of smoking and alcohol consumption was five and three times higher in males vs. females. We found a positive association between KS and heavy vs. non-drinking (ORadj=1.31;95%CI=1.03–1.67), and in current heavy vs. never smokers (ORadj=1.82;95%CI=1.07–3.10). These associations remained positive for alcohol consumption (but with wider CIs) after stratification by sex, and restriction to HIV positive participants. We found no evidence of interactions of smoking and alcohol by sex. Smoking and alcohol consumption may provide a possible explanation for the KS sex differences, given both exposures are more common in men, but confounding and bias cannot be fully ruled out. The role smoking and alcohol play in relation to viral loads of HIV/KSHV, differences in immunological responses or other genetic differences between males and females warrant further studies.

Cervical cancer is the second most common female gynaecological malignancy in sub-Saharan Africa (SSA). Previous genome-wide association studies (GWASs) identified genetic variants associated with cervical cancer in women of European and Asian ancestry, particularly within the major histocompatibility complex (MHC). However, owing to the complexity of linkage disequilibrium and varied environmental exposures in different ancestral populations, regional GWASs are needed to investigate the genetic contribution to the pathogenesis of cervical cancer in continental African populations. A total of 1,637 cervical cancer patients and 761 controls in women of African ancestry were identified from the Johannesburg Cancer Study and the AWI-Gen study, respectively. DNA samples were genotyped on the 2.3 million H3Africa GWAS SNP array and genotyped SNPs imputed to a total of 13,937,308 SNPs. The association between genetic variants and cervical cancer was tested using linear mixed models, adjusting for five principal components and cryptic relatedness. We identified one locus within the MHC region associated with cervical cancer at genome-wide significance, led by rs3129965 (odds ratio [OR] = 0.89, 95% confidence interval [CI] = 0.87-0.92, P = 2.292 x 10-11) near HLA-DRA. Four other loci were strongly associated with cervical cancer (P Citation Format: Abram Bunya Kamiza, Wenlong Carl Chen, Jean-Tristan Brandenberg, Michele Ramsay, Christopher G. Mathew. A genome-wide association study identifies the association of common variants in the major histocompatibility complex with cervical cancer in black South African women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 766.

We reviewed the literature on the importance of selected anti-high-risk human papillomavirus (HR-HPV) antibodies (namely, 16/18 and early oncoproteins E6 and E7) as potential serological markers for early detection of individuals at high risk of cervical cancer. We searched for studies in PubMed and Embase databases published from 2010 to 2020 on antibodies against HR-HPV E6 and E7 early proteins and cervical cancer. Pooled sensitivity and specificity for HPV16 and HPV18 antibodies were calculated using a bivariate hierarchical random-effects model. A total of 69 articles were identified; we included three studies with 1550 participants. For the three HPV16/18 E6 and E7 antibody tests, enzyme-linked immunosorbent assay-based assays had a sensitivity of 18% for detecting CIN2+ (95% confidence interval [CI]: 15-21) and a specificity of 96% (95% CI: 92-98), for slot-blot, sensitivity was 28.9% (95% CI: 23.3-35.1) and specificity was 72% (95% CI: 66.6-77.0) for detecting CIN2+, and for multiplex HPV serology assay based on a glutathione S-transferase, sensitivity was 16% (95% CI: 8.45-28.6) and specificity was 98% (95% CI: 97-99) for detecting invasive cervical cancer. HR-HPV16/18 E6 and E7 serological markers showed high specificity, but sensitivity was suboptimal for the detection of cervical cancer in either population screening settings or as point-of-care screening tests.

Contains fulltext : 248656.pdf (Publisher’s version ) (Closed access) BACKGROUND: Sex differences in incidence and/or presentation of schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BIP) are pervasive. Previous evidence for shared genetic risk and sex differences in brain abnormalities across disorders suggest possible shared sex-dependent genetic risk. METHODS: We conducted the largest to date genome-wide genotype-by-sex (G×S) interaction of risk for these disorders using 85,735 cases (33,403 SCZ, 19,924 BIP, and 32,408 MDD) and 109,946 controls from the PGC (Psychiatric Genomics Consortium) and iPSYCH. RESULTS: Across disorders, genome-wide significant single nucleotide polymorphism-by-sex interaction was detected for a locus encompassing NKAIN2 (rs117780815, p = 3.2 × 10(-8)), which interacts with sodium/potassium-transporting ATPase (adenosine triphosphatase) enzymes, implicating neuronal excitability. Three additional loci showed evidence (p < 1 × 10(-6)) for cross-disorder G×S interaction (rs7302529, p = 1.6 × 10(-7); rs73033497, p = 8.8 × 10(-7); rs7914279, p = 6.4 × 10(-7)), implicating various functions. Gene-based analyses identified G×S interaction across disorders (p = 8.97 × 10(-7)) with transcriptional inhibitor SLTM. Most significant in SCZ was a MOCOS gene locus (rs11665282, p = 1.5 × 10(-7)), implicating vascular endothelial cells. Secondary analysis of the PGC-SCZ dataset detected an interaction (rs13265509, p = 1.1 × 10(-7)) in a locus containing IDO2, a kynurenine pathway enzyme with immunoregulatory functions implicated in SCZ, BIP, and MDD. Pathway enrichment analysis detected significant G×S interaction of genes regulating vascular endothelial growth factor receptor signaling in MDD (false discovery rate-corrected p < .05). CONCLUSIONS: In the largest genome-wide G×S analysis of mood and psychotic disorders to date, there was substantial genetic overlap between the sexes. However, significant sex-dependent effects were enriched for genes related to neuronal development and immune and vascular functions across and within SCZ, BIP, and MDD at the variant, gene, and pathway levels.

Kaposi’s sarcoma (KS) has become a common AIDS-defining cancer in sub-Saharan Africa. Kaposi’s sarcoma-associated human herpesvirus strongly modulated by HIV-related immune suppression are the principal causes of this cancer. No other risk factors have been identified as playing a strong role. HIV prevention programs and good coverage of antiretroviral therapy (ART) in developed countries resulted in a remarkable decline in HIV-KS incidence and better KS prognosis. By contrast, in sub-Saharan Africa, population ART rollout has lagged, but clinical studies have shown positive results in reduction of KS incidence and better KS prognosis. However, the effect of ART rollout in relation to population KS incidence is unclear. We describe the incidence of KS in sub-Saharan Africa, in four time-periods, (1) before 1980 (before HIV/AIDS era); (2) 1981–2000 (early HIV/AIDS era, limited or no ART coverage); (3) 2001–2010 (early ART coverage period); and (4) 2011–2016 (fair to good ART coverage period). We used KS incidence data available from WHO-International Agency for Research on Cancer (IARC) publications and the Africa Cancer Registry Network. National HIV prevalence and ART coverage data were derived from UNAIDS/WHO. A rapid increase in KS incidence was observed throughout sub-Saharan Africa as the HIV epidemic progressed, reaching peak incidences in Period 2 (pre-ART rollout) of 50.8 in males and 20.3 per 100 000 in females (Zimbabwe, Harare). The overall unweighted average decline in KS incidence between 2000 and 2010 and 2011–2016 was 27%, but this decline was not statistically significant across the region. ART rollout coincides with a decline in KS incidence across several regions in sub-Saharan Africa. The importance of other risk factors such as reductions in HIV incidence could not be ascertained.

Background In populations with high rates of human immunodeficiency virus (HIV)-coinfection, the nature of the relationship between human papillomavirus (HPV)-16 and -18 (L1, E6 and E7) antibodies and cervical cancer is still uncertain. We measured the association between seropositivity to HPV (L1, E6 and E7) proteins and cervical cancer among black South African women with and without HIV co-infection. Methods We used questionnaire data and serum collected from consecutively recruited patients with a newly diagnosed cancer from the Johannesburg Cancer Study from 1346 cervical cancer cases and 2532 controls (diagnosed with other non-infection related cancers). Seropositivity to HPV proteins was measured using a multiplex serological assay based on recombinant glutathione S-transferase (GST) fusion proteins. We measured associations between their presence and cervical cancer using unconditional logistic regression models and evaluated the sensitivity and specificity of these HPV biomarkers. Results Among controls, HIV-negative women from rural areas compared to urban had significantly higher HPV seroprevalence, HPV16 E7 (8.6% vs 3.7%) and HPV18 E7 (7.9% vs 2.0%). HPV16 E6 and E7 antibodies were positively associated with cervical cancer in HIV-positive (Adjusted Odds Ratio (AOR) = 33; 95% CI 10–107) and HIV-negative women (AOR = 97; 95% CI 46–203). In HIV-positive women, HPV E6/E7 antibodies had low sensitivity (43.0%) and high specificity (90.6%) for cervical cancer detection. In HIV-negative women, HPV E6/E7 antibodies sensitivity was 70.6% and specificity was 89.7%. Conclusions Our data show that HPV (L1, especially E6 and E7) antibody positivity is associated with cervical cancer in both HIV-positive and HIV-negative women. Nonetheless, being HIV-positive plays an important role in the development of cervical cancer.

Breast cancer (BC) is the most common cancer among African women and is the second most common cause of cancer deaths in Africa as estimated by GLOBOCAN 2018.1 Cancer incidence is increasing in Africa1 and is associated largely with lifestyle changes, resulting from increased urbanization.2 Ferlay et al3 predicted a 49% increase in BC incidence across Africa between 2018 and 2040, an increase faster than any other region in the world. The International Association of Cancer Registries cancer incidence report includes data for only 20 of 46 sub-Saharan African (SSA) countries,4 and it is likely that the incidence of BC is under-reported owing to lack of infrastructure for cancer diagnosis in resource-constrained countries in SSA.5 Also, owing to the large burden of communicable and other noncommunicable diseases in SSA, most resources are directed at controlling these diseases.6,7 Cancer research, especially molecular research, in SSA is often deprioritized against other pressing public health concerns.8 CONTEXT Key Objective Both rare and common genetic variants contribute to the risk of breast cancer (BC). Much is known about the genetics of BC in populations of European origin. Our objective was to review studies of genetic susceptibility to BC in the populations of sub-Saharan Africa to identify knowledge gaps and propose study designs to address these. Knowledge Generated A total of 22 studies were identified in 10 of 46 countries in sub-Saharan Africa. Rare variants predicted to be pathogenic were detected most commonly in the BRCA1, BRCA2, and PALB2 genes. There were few studies of common genetic variants, none of which provided strong evidence for association with BC risk. Relevance Knowledge of genetic factors contributing to BC risk has important implications for patients and their families both for genetic counseling and for potential access to new therapies, which improve survival and reduce side effects.

Background The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was launched in 2000 with the goal of eliminating lymphatic filariasis (LF) as a public health problem by 2020. Despite considerable progress, the current prevalence is around 60% of the 2000 figure, with the deadline looming a year away. Consequently, there is a continued need for investment in both the mass drug administration (MDA) and morbidity management programs, and this paper aims to demonstrate that need by estimating the health and economic burdens of LF prior to MDA programs starting in GPELF areas. Methods A previously developed model was used to estimate the numbers of individuals infected and individuals with symptomatic disease, along with the attributable number of disability-adjusted life years (DALYs). The economic burden was calculated by quantifying the costs incurred by the health-care system in managing clinical cases, the patients’ out-of-pocket costs, and their productivity costs. Results Prior to the MDA program, approximately 129 million people were infected with LF, of which 43 million had clinical disease, corresponding to a DALY burden of 5.25 million. The average annual economic burden per chronic case was US $115, the majority of which resulted from productivity costs. The total economic burden of LF was estimated at US $5.8 billion annually. Conclusions These results demonstrate the magnitude of the LF burden and highlight the continued need to support the GPELF. Patients with clinical disease bore the majority of the economic burden, but will not benefit much from the current MDA program, which is aimed at reducing transmission. This assessment further highlights the need to scale up morbidity management programs.

Atherosclerosis precedes the onset of many clinical manifestations of cardiovascular diseases (CVDs). We used carotid intima-media thickness (cIMT) to investigate genetic susceptibility to atherosclerosis in 7894 unrelated adults (3963 women, 3931 men) aged 40 to 60 years resident in four sub-Saharan African countries. cIMT was measured by ultrasound and genotyping was performed on the H3Africa SNP Array. Two new African-specific genome-wide significant loci, SIRPA (p=4.7E-08), and FBXL17 (p=2.5E-08), were identified in the combined dataset. Sex-stratified analysis revealed associations with two male-specific loci, SNX29 (p=6.3E-09) and MAP3K7 (p=5.3E-08), and two female-specific loci, LARP6 (p=2.4E-09) and PROK1 (p=1.0E-08). Regional associations were replicated with known risk loci for atherosclerosis and CVDs with different lead SNPs than in Europeans and significant enrichment for oestrogen response genes for female-specific signals were identified. The genes identified showed biological relevance to atherosclerosis and/or CVDs, as well as sex-differences and transferability of signals from non-African studies.

Atherosclerosis precedes the onset of clinical manifestations of cardiovascular diseases (CVDs). We used carotid intima-media thickness (cIMT) to investigate genetic susceptibility to atherosclerosis in 7894 unrelated adults (3963 women, 3931 men; 40 to 60 years) resident in four sub-Saharan African countries. cIMT was measured by ultrasound and genotyping was performed on the H3Africa SNP Array. Two new African-specific genome-wide significant loci for mean-max cIMT, SIRPA (p = 4.7E-08), and FBXL17 (p = 2.5E-08), were identified. Sex-stratified analysis revealed associations with one male-specific locus, SNX29 (p = 6.3E-09), and two female-specific loci, LARP6 (p = 2.4E-09) and PROK1 (p = 1.0E-08). We replicate previous cIMT associations with different lead SNPs in linkage disequilibrium with SNPs primarily identified in European populations. Our study find significant enrichment for genes involved in oestrogen response from female-specific signals. The genes identified show biological relevance to atherosclerosis and/or CVDs, sex-differences and transferability of signals from non-African studies.

TP53 plays a crucial role in preventing cancer development. Previous studies in sub-Saharan Africa (SSA) reported inconclusive findings for the association of the TP53 rs1042522 C G variant with cervical cancer. We therefore performed a meta-analysis to summarise this association in the SSA population.Online databases were searched to identify suitable articles according to the PRISMA guidelines. We included studies published in English or French that provided the sample sizes and genotype counts for both cases and controls and evaluated the association between TP53 rs1042522 and cervical cancer in the SSA population. A fixed-effect model was used to calculate the pooled odds ratio (OR) and 95% confidence intervals (95% CIs).A total of 699 cervical cancer cases and 1008 controls from eight studies in SSA were included in this meta-analysis. Women harbouring the variant G allele of the TP53 rs1042522 were at increased risk of cervical cancer in allelic (G vs. C; OR = 1.30, 95% Cl = 1.12-1.50), homozygous (GG vs. CC; OR = 1.62, 95% CI = 1.20-2.19) and recessive (GG vs. CG + GG; OR = 1.74, 95% CI = 1.34-2.25) genetic models. However, the dominant genetic model (CG + GG vs. CC; OR = 1.20, 95% CI = 0.96-1.48) was not significantly associated with cervical cancer.Our meta-analysis revealed that harbouring variant G allele of TP53 rs1042522 is associated with cervical cancer risk in the SSA population.Le TP53 joue un rôle crucial dans la prévention du développement du cancer. Des études antérieures en Afrique subsaharienne (ASS) ont rapporté des résultats non concluants pour l'association de la variante TP53 rs1042522 CG avec le cancer du col de l'utérus. Nous avons donc réalisé une méta-analyse pour résumer cette association dans la population SSA. MÉTHODES: Les bases de données en ligne ont été recherchées pour identifier les articles appropriés selon les directives PRISMA. Nous avons inclus des études publiées en anglais ou en français qui ont fourni la taille des échantillons et le nombre de génotypes pour les cas et les témoins et évalué l'association entre TP53 rs1042522 et le cancer du col de l'utérus dans la population SSA. Un modèle à effet fixe a été utilisé pour calculer le rapport de cotes combiné (OR) et les intervalles de confiance à 95% (IC95%). RÉSULTATS: Un total de 699 cas de cancer du col utérin et 1008 témoins de huit études en ASS ont été inclus dans cette méta-analyse. Les femmes hébergeant l'allèle variant G du TP53 rs1042522 présentaient un risque accru de cancer du col de l'utérus chez les modèles génétiques alléliques (G vs C; OR = 1,30, IC95%: 1,12-1,50), homozygotes (GG vs CC; OR = 1,62, IC95%: 1,20-2,19) et récessifs (GG vs.CG + GG; OR = 1,74, IC95%: 1,34-2,25). Cependant, le modèle génétique dominant (CG + GG vs CC; OR = 1,20, IC95%: 0,96-1,48) n'était pas significativement associé au cancer du col utérin.Notre méta-analyse a révélé que l'hébergement de l'allèle variant G de TP53 rs1042522 est associé au risque de cancer du col de l'utérus dans la population SSA.

The Johannesburg Cancer Study (JCS) aims were to examine whether cancer risk factors identified in Western countries applied to black patients in Johannesburg, South Africa and to understand the impact of HIV on cancer risk, with a view to identifying previously unrecognised HIV associated cancers. A total of 24 971 black patients with an incident histologically proven (>95%) cancer of any type were enrolled between 1995-2016. Response rates were >90%. Patients provided informed consent, lifestyle and demographic information using a structured questionnaire; 19 351 provided a serum sample and 18 972 a whole blood sample for genomic analyses. This is currently the largest cancer epidemiological biobank in Africa. JCS uses a cancer case-control method; controls being cancer types unrelated to exposures of interest. Published results show the importance of HIV in several cancers known to be infection associated e.g. Kaposi sarcoma (OR = 1683; CI = 595-5194) in those with high Kaposi-sarcoma-associated-herpesvirus titres; no effect of HIV on lung or liver cancer-in the latter showing a strong association with HBVDNA, sAg and c positivity (OR = 47; CI = 21-104). Comparable data to higher-income country studies include lung cancer ORs in relation to smoking (15+g tobacco/day) (ORMales = 37; CI = 21-67, ORFemales = 18.5; CI = 8-45) and associations between alcohol and oesophageal cancer in smokers (ORM&F = 4.4; CI = 3-6). Relationship between hormonal contraception declined to null 10 or more years after stopping for breast (OR = 1.1; CI = 0.9-1.4) and cervical cancer (OR = 1.0;CI = 0.8-1.2), and protective effects shown, five or more years after stopping for ovarian (OR = 0.6; CI = 0.4-1) and endometrial cancer (OR = 0.4; CI = 0.2-0.9). Preferential access is based on data requests promoting data pooling, equal collaborative opportunities and enhancement of research capacity in South Africa. The JCS is a practical and valid design in otherwise logistically difficult settings.

Esophageal squamous cell carcinoma (ESCC) has a high incidence in sub-Saharan Africa and a poor prognosis, but little is known about the genetic contribution to ESCC susceptibility in this region. We carried out a GWAS in the South African Black (SAB) population with 1,686 ESCC cases and 3,217 controls as part of the Evolving Risk Factors for Cancer in African populations (ERICA-SA) study after ethical approval and informed consent. ESCC case samples from ERICA-SA and controls from the H3A AWI-Gen study were genotyped on the 2.3 million H3 Africa SNP Illumina array and additional SNPs imputed using the Wellcome Sanger Institute imputation service. Measures for correction of population structure included Eigen decomposition for Principal Component (PC) analysis. The final imputed dataset of 14.4M SNPs for 1,686 OSCC cases and 3,217 population controls was used in linear-mixed model analysis to test for association using GEMMA. A meta-analysis of SNP sets common to both our study and a GWAS of 2,013 Chinese ESCC cases and 2,701 controls was done using METAL. The GWAS of the SAB population identified a total of 62 SNPs with suggestive association with ESCC (P < 5x10-6), from 29 independent potential risk loci. A strong signal at genome-wide significance is located upstream of the FAM120A gene on chromosome 9 (rs1237966, p=4.58x10-8) and is supported by multiple SNPs at this locus. FAM120A encodes an RNA binding protein which is a critical component of oxidative stress-induced signalling. A strong association was also observed on chromosome 2, led by rs142741123 (p=5.49x10-8) in a region spanning the MYO1B and STAT4 genes with SNPs that are absent in non-African populations, suggesting that this is an African-specific risk locus for ESCC. There was limited support for the association of ESCC risk loci reported in other populations in our study. We did a meta-analysis of the SAB GWAS with a published GWAS of Chinese ESSC cases and controls with 4.85 million SNPs shared between the two studies. A total of 12 SNPs were associated with ESCC at genome-wide significance. These included 3 loci: chromosome 9, led by rs12379660 (p-valuemeta = 9.36x10-10), chromosome 10 led by rs7099485 (p-valuemeta = 1.48x10-8) and chromosome 22 led by rs1033667 (p-valuemeta = 1.47x10-9). The chromosome 9 locus at FAM120A is the novel locus identified in our African ESCC GWAS, the chromosome 10 locus at PLCE1 shows association only in the Chinese GWAS, and the chromosome 22 locus at CHEK2 was previously identified in the Chinese ESCC GWAS, and is supported further by the African ESCC GWAS. This study is, to our knowledge, the first cancer GWAS conducted in solely in a resident African population, and has detected two novel risk loci for ESCC at or near genome-wide significance, one of which is likely specific to African populations. It also demonstrates the power of trans-ethnic meta-analysis to identify common or distinct risk loci in populations of diverse ancestry. Citation Format: Wenlong C. Chen, Jean-Tristan Brandenburg, Ananyo Choudhury, Mahtaab Hayat, Dhriti Sengupta, Chantal Babb de Villiers, Lucien Ferndale, Cassandra Soo, Sang H. Lee, Charles Curtis, Robert Newton, Tim Waterboer, Frederic Sitas, Michele Ramsay, Christian C. Abnet, Colleen Aldous, Mohamed I. Parker, Elvira Singh, Deborah Bradshaw, Cathryn M. Lewis, Christopher G. Mathew. Genome-wide association study of African esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 31.

Inflammatory bowel diseases are chronic gastrointestinal inflammatory disorders that affect millions of people worldwide. Genome-wide association studies have identified 200 inflammatory bowel disease-associated loci, but few have been conclusively resolved to specific functional variants. Here we report fine-mapping of 94 inflammatory bowel disease loci using high-density genotyping in 67,852 individuals. We pinpoint 18 associations to a single causal variant with greater than 95% certainty, and an additional 27 associations to a single variant with greater than 50% certainty. These 45 variants are significantly enriched for protein-coding changes (n = 13), direct disruption of transcription-factor binding sites (n = 3), and tissue-specific epigenetic marks (n = 10), with the last category showing enrichment in specific immune cells among associations stronger in Crohn's disease and in gut mucosa among associations stronger in ulcerative colitis. The results of this study suggest that high-resolution fine-mapping in large samples can convert many discoveries from genome-wide association studies into statistically convincing causal variants, providing a powerful substrate for experimental elucidation of disease mechanisms.

A. Palotie on työryhmän Int IBD Genetics Consortium jäsen. One goal of human genetics is to understand the genetic basis of disease, a challenge for diseases of complex inheritance because risk alleles are few relative to the vast set of benign variants. Risk variants are often sought by association studies in which allele frequencies in case subjects are contrasted with those from population-based samples used as control subjects. In an ideal world we would know population-level allele frequencies, releasing researchers to focus on case subjects. We argue this ideal is possible, at least theoretically, and we outline a path to achieving it in reality. If such a resource were to exist, it would yield ample savings and would facilitate the effective use of data repositories by removing administrative and technical barriers. We call this concept the Universal Control Repository Network (UNICORN), a means to perform association analyses without necessitating direct access to individual-level control data. Our approach to UNICORN uses existing genetic resources and various statistical tools to analyze these data, including hierarchical clustering with spectral analysis of ancestry; and empirical Bayesian analysis along with Gaussian spatial processes to estimate ancestry-specific allele frequencies. We demonstrate our approach using tens of thousands of control subjects from studies of Crohn disease, showing how it controls false positives, provides power similar to that achieved when all control data are directly accessible, and enhances power when control data are limiting or even imperfectly matched ancestrally. These results highlight how UNICORN can enable reliable, powerful, and convenient genetic association analyses without access to the individual-level data.

Background Human leukocyte antigens (HLA) are encoded by closely linked genetic loci, and are important in cervical carcinogenesis. The association between HLA-DRB1 alleles with cervical cancer has been studied extensively, but results reported thus far have been inconsistent. Hence, we performed a meta-analysis to precisely assess this association. Methods A literature search was conducted in various online databases to identify suitable articles. Case-control studies investigating the association between HLA-DRB1 alleles and cervical cancer were included in this study. Fixed and random-effect models were used to calculate the pooled odds ratio (OR) and 95% confidence intervals (CIs). Results A total of 6645 cases and 9095 controls from 36 case-control studies were included. Of the 13 HLA-DRB1 family alleles, DRB1*09 (OR = 1.30) and DRB1 *15 (OR = 1.60) were associated with cervical cancer risk, whilst DRB1*13 (OR = 0.66) exerted a protective effect. Among the 44 HLA-DRB1 specific alleles, DRB1*04:01 (OR = 1.25), DRB1*10:01 (OR = 1.45), DRB1*11:01 (OR = 1.32), DRB1*15:01 (OR = 1.21) and DRB1*15:02 (OR = 1.55) were associated with an increased risk of cervical cancer. However, DRB1*04:06 (OR = 0.52), DRB1*12:02 (OR = 0.61), DRB1*13:01 (OR = 0.62), DRB1*13:02 (OR = 0.57), and DRB1*14:04 (OR = 0.37) were associated with a decreased risk of cervical cancer. Subgroup analysis also revealed that HLA-DRB1 alleles are associated with cervical cancer in Asian, Caucasian, Hispanic or Latin American and black sub-Saharan Africa populations. Conclusion Our meta-analysis revealed that multiple HLA-DRB1 alleles are associated with cervical cancer in women of diverse ancestry populations.

BACKGROUND & AIMS: Relatives of individuals with Crohn's disease (CD) carry CD-associated genetic variants and are often exposed to environmental factors that increase their risk for this disease. We aimed to estimate the utility of genotype, smoking status, family history, and other biomarkers can be used to calculate risk in asymptomatic first-degree relatives of patients with CD.METHODS: We recruited 480 healthy first-degree relatives (full siblings, offspring or parents) of patients with CD through the Guy's and St Thomas' NHS Foundation Trust and from members of Crohn's and Colitis, United Kingdom. DNA samples were genotyped using the Immunochip. We calculated a risk score for 454 participants, based on 72 genetic variants associated with CD, family history, and smoking history. Participants were assigned to highest and lowest risk score quartiles. We assessed pre-symptomatic inflammation by capsule endoscopy and measured 22 markers of inflammation in stool and serum samples (reference standard). Two machine-learning classifiers (elastic net and random forest) were used to assess the ability of the risk factors and biomarkers to identify participants with small intestinal inflammation in the same dataset.RESULTS: The machine-learning classifiers identified participants with pre-symptomatic intestinal inflammation: elastic net (area under the curve, 0.80; 95% CI, 0.62-0.98) and random forest (area under the curve, 0.87; 95% CI, 0.75-1.00). The elastic net method identified 3 variables that can be used to calculate odds for intestinal inflammation: combined family history of CD (odds ratio, 1.31), genetic risk score (odds ratio, 1.14), and fecal level of calprotectin (odds ratio, 1.04). These same 3 variables were among the 5 factors associated with intestinal inflammation in the random forest model.CONCLUSION: Using machine learning classifiers, we found that genetic variants associated with CD, family history, and fecal level of calprotectin together identify individuals with pre-symptomatic intestinal inflammation who are therefore at risk for CD. A tool for detecting people at risk for CD before they develop symptoms would help identify the individuals most likely to benefit from early intervention.

Oesophageal squamous cell carcinoma (OSCC) has a high incidence in southern Africa and a poor prognosis. Limited information is available on the contribution of genetic variants in susceptibility to OSCC in this region. However, recent genome-wide association studies have identified multiple susceptibility loci in Asian and European populations. In this study, we investigated genetic variants from seven OSCC risk loci identified in non-African populations for association with OSCC in the South African Black population. We performed association studies in a total of 1471 cases and 1791 controls from two study sample groups, which included 591 cases and 852 controls from the Western Cape and 880 cases and 939 controls from the Johannesburg region in the Gauteng province. Thereafter, we performed a meta-analysis for 11 variants which had been genotyped in both studies. A single nucleotide polymorphism in the CHEK2 gene, rs1033667, was significantly associated with OSCC [P = 0.002; odds ratio (OR) = 1.176; 95% confidence interval (CI): 1.06–1.30]. However, single nucleotide polymorphisms in the CASP8/ALS2CR12, TMEM173, PLCE1, ALDH2, ATP1B2/TP53 and RUNX1 loci were not associated with the disease (P > 0.05). The lack of association of six of these loci with OSCC in South African populations may reflect different genetic risk factors in non-African and African populations or differences in the genetic architecture of African genomes. The association at CHEK2, a gene with key roles in cell cycle regulation and DNA repair, in an African population provides further support for the contribution of common genetic variants at this locus to the risk of oesophageal cancer., Single nucleotide polymorphisms (SNPs) associated with oesophageal squamous cell carcinoma (OSCC) in Asian populations were genotyped in OSCC cases and controls from the South African Black population. A SNP in CHEK2 was associated with an increased risk of OSCC.

Fluoropyrimidines, including 5-fluororacil (5FU) and its pro-drug Capecitabine, are the common treatment for colorectal, breast, neck and head cancers—either as monotherapy or in combination therapy. Adverse reactions (ADRs) to the treatment are common and often result in treatment discontinuation or dose reduction. Factors contributing to ADRs, including genetic variation, are poorly characterized. We performed exome array analysis to identify genetic variants that contribute to adverse reactions. Our final dataset consisted of 504 European ancestry individuals undergoing fluoropyrimidine-based therapy for gastrointestinal cancer. A subset of 254 of these were treated with Capecitabine. All individuals were genotyped on the Illumina HumanExome Array. Firstly, we performed SNP and gene-level analyses of protein-altering variants on the array to identify novel associations the following ADRs, which were grouped into four phenotypes based on symptoms of diarrhea, mucositis, and neutropenia and hand-and-foot syndrome. Secondly, we performed detailed analyses of the HLA region on the same phenotypes after imputing the HLA alleles and amino acids. No protein-altering variants, or sets of protein-altering variants collapsed into genes, were associated with the main outcomes after Bonferroni correction. We found evidence that the HLA region was enriched for associations with Hand-and-Foot syndrome (p = 0.023), but no specific SNPs or HLA alleles were significant after Bonferroni correction. Larger studies will be required to characterize the genetic contribution to ADRs to 5FU. Future studies that focus on the HLA region are likely to be fruitful.

Background and aimsAlthough genome-wide association studies (GWAS) in inflammatory bowel disease (IBD) have identified a large number of common disease susceptibility alleles for both Crohn’s disease (CD) and ulcerative colitis (UC), a substantial fraction of IBD heritability remains unexplained, suggesting that rare coding genetic variants may also have a role in pathogenesis. We used high-throughput sequencing in families with multiple cases of IBD, followed by genotyping of cases and controls, to investigate whether rare protein altering genetic variants are associated with susceptibility to IBD.MethodsWhole exome sequencing was carried out in 10 families in which 3 or more individuals were affected with IBD. A stepwise filtering approach was applied to exome variants to identify potential causal variants. Follow-up genotyping was performed in 6,025 IBD cases (2,948 CD; 3,077 UC) and 7,238 controls.ResultsOur exome variant analysis revealed coding variants in the NLRP7 gene that were present in affected individuals in two distinct families. Genotyping of the two variants, p.S361L and p.R801H, in IBD cases and controls showed that the p.S361L variant was significantly associated with an increased risk of ulcerative colitis (odds ratio 4.79, p=0.0039) and IBD (odds ratio 3.17, p=0.037). A combined analysis of both variants showed suggestive association with an increased risk of IBD (odds ratio 2.77, p=0.018).ConclusionsThe results suggest that NLRP7 signalling and inflammasome formation may be a significant component in the pathogenesis of IBD.

Long-term storage of whole blood can affect the integrity of DNA if it is not done under optimal conditions. The aim of this study was to determine whether long-term storage (2-19 years) of whole blood samples at -30°C had a negative effect on the quality or quantity of genomic DNA that could be recovered at extraction. Genomic DNA was isolated from 2758 whole blood samples collected in 4 mL EDTA vacutainers from 1997 to 2012. DNA was extracted using the Qiagen

Esophageal cancer is the eighth most common cancer worldwide and the sixth most common cause of cancer-related death; however, worldwide incidence and mortality rates do not reflect the geographic variations in the occurrence of this disease. In recent years, increased attention has been focused on the high incidence of esophageal squamous cell carcinoma (ESCC) throughout the eastern corridor of Africa, extending from Ethiopia to South Africa. Nascent investigations are underway at a number of sites throughout the region in an effort to improve our understanding of the etiology behind the high incidence of ESCC in this region. In 2017, these sites established the African Esophageal Cancer Consortium. Here, we summarize the priorities of this newly established consortium: to implement coordinated multisite investigations into etiology and identify targets for primary prevention; to address the impact of the clinical burden of ESCC via capacity building and shared resources in treatment and palliative care; and to heighten awareness of ESCC among physicians, at-risk populations, policy makers, and funding agencies.

Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus (r = −0.62, P = 5.30 × 10−5) but not between CCT and primary open-angle glaucoma (r = −0.17, P = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation.

Background and Aim Escherichia coli can be isolated from lamina propria macrophages in Crohn's disease (CD), and their intramacrophage persistence may provide a stimulus for inflammation. To further determine the contributions of macrophage dysfunction and E. coli pathogenicity to this, we aimed to compare in vitro functioning of macrophages from patients with CD and healthy controls (HC) in response to infection with CD-derived adherent-invasive E. coli (AIEC) and less pathogenic E. coli strains. Methods Monocyte-derived macrophages were cultured from patients with CD and HC. Intramacrophage survival of E. coli strains (CD-derived adherent-invasive [AI] and non-AI strains and laboratory strain K-12) was compared. Macrophage cytokine release (tumor necrosis factor alpha [TNFα], interleukin [IL]-23, IL-8 and IL-10) and monocyte phagoctyosis and respiratory burst function were measured after E. coli infection. For CD patients, laboratory data were correlated with clinical phenotype, use of immunomodulation, and CD risk alleles (NOD2, IL-23R, ATG16L1 and IRGM). Results Attenuated TNFα and IL-23 release from CD macrophages was found after infection with all E. coli strains. There was prolonged survival of CD-derived AIEC, CD-derived non-AIEC and E. coli K-12 in macrophages from CD patients compared to within those from HC. No abnormality of monocyte phagocytosis or respiratory burst function was detected in CD. Macrophage dysfunction in CD was not influenced by phenotype, use of immunomodulation or genotype. Conclusions CD macrophage responses to infection with E. coli are deficient, regardless of clinical phenotype, CD genotype or E. coli pathogenicity. This suggests host immunodeficiency is an important contributor to intramacrophage E. coli persistence in CD.

ObjectiveRelatives of individuals with Crohn’s disease (CD) carry an increased number of CD-associated genetic variants and are at increased risk of developing the disease. Multiple environmental and genetic factors contribute to this increased risk. We aimed to estimate the utility of genotype, smoking, family history, and a panel of biomarkers to predict risk in asymptomatic first-degree relatives (FDRs) of CD patients.DesignWe calculated a combined genotype (72 CD-associated genetic markers) and smoking relative risk score in 454 FDRs, and performed capsule endoscopy and collected 22 biomarkers in individuals from the highest and lowest risk quartiles. We then predicted small intestinal inflammation using genetic risk score, smoking status, number of relatives with CD, capsule transit time, and the panel of biomarkers in 124 individuals with complete data. Our principal analysis was to calculate the predictive utility from two machine learning classifiers: an elastic net and a random forest.ResultsBoth classifiers successfully predicted FDRs with intestinal inflammation: elastic net (AUC=0.80, 95% CI: 0.62-0.98), random forest (AUC=0.87, 95% CI: 0.75-1.00). The elastic net selected a 3-predictor solution: CD family history (OR=1.31), genetic risk score (OR=1.14), and faecal calprotectin (OR=1.04). The same 3 variables were among the top 5 most important predictors as ranked by the random forest.ConclusionA readily collectable panel of genetic risk variants, added to family history and faecal calprotectin, predicts those at greatest risk for developing CD with a good degree of accuracy.

Background and Aims Although genome-wide association studies [GWAS] in inflammatory bowel disease [IBD] have identified a large number of common disease susceptibility alleles for both Crohn’s disease [CD] and ulcerative colitis [UC], a substantial fraction of IBD heritability remains unexplained, suggesting that rare coding genetic variants may also have a role in pathogenesis. We used high-throughput sequencing in families with multiple cases of IBD, followed by genotyping of cases and controls, to investigate whether rare protein-altering genetic variants are associated with susceptibility to IBD. Methods Whole-exome sequencing was carried out in 10 families in whom three or more individuals were affected with IBD. A stepwise filtering approach was applied to exome variants, to identify potential causal variants. Follow-up genotyping was performed in 6025 IBD cases [2948 CD; 3077 UC] and 7238 controls. Results Our exome variant analysis revealed coding variants in the NLRP7 gene that were present in affected individuals in two distinct families. Genotyping of the two variants, p.S361L and p.R801H, in IBD cases and controls showed that the p.S361L variant was significantly associated with an increased risk of ulcerative colitis [odds ratio 4.79, p = 0.0039] and IBD [odds ratio 3.17, p = 0.037]. A combined analysis of both variants showed suggestive association with an increased risk of IBD [odds ratio 2.77, p = 0.018]. Conclusions The results suggest that NLRP7 signalling and inflammasome formation may be a significant component in the pathogenesis of IBD.

The International Agency for Research on Cancer (IARC) and the US National Cancer Institute (NCI) have initiated a series of cancer-focused seminars [Scelo G, Hofmann JN, Banks RE et al. International cancer seminars: a focus on kidney cancer. Ann Oncol 2016; 27(8): 1382-1385]. In this, the second seminar, IARC and NCI convened a workshop in order to examine the state of the current science on esophageal squamous cell carcinoma etiology, genetics, early detection, treatment, and palliation, was reviewed to identify the most critical open research questions. The results of these discussions were summarized by formulating a series of 'difficult questions', which should inform and prioritize future research efforts.

To ensure efficient genome duplication, cells have evolved numerous factors that promote unperturbed DNA replication and protect, repair and restart damaged forks. Here we identify downstream neighbor of SON (DONSON) as a novel fork protection factor and report biallelic DONSON mutations in 29 individuals with microcephalic dwarfism. We demonstrate that DONSON is a replisome component that stabilizes forks during genome replication. Loss of DONSON leads to severe replication-associated DNA damage arising from nucleolytic cleavage of stalled replication forks. Furthermore, ATM- and Rad3-related (ATR)-dependent signaling in response to replication stress is impaired in DONSON-deficient cells, resulting in decreased checkpoint activity and the potentiation of chromosomal instability. Hypomorphic mutations in DONSON substantially reduce DONSON protein levels and impair fork stability in cells from patients, consistent with defective DNA replication underlying the disease phenotype. In summary, we have identified mutations in DONSON as a common cause of microcephalic dwarfism and established DONSON as a critical replication fork protein required for mammalian DNA replication and genome stability.

Genetic association studies have identified 215 risk loci for inflammatory bowel disease, thereby uncovering fundamental aspects of its molecular biology. We performed a genome-wide association study of 25,305 individuals and conducted a meta-analysis with published summary statistics, yielding a total sample size of 59,957 subjects. We identified 25 new susceptibility loci, 3 of which contain integrin genes that encode proteins in pathways that have been identified as important therapeutic targets in inflammatory bowel disease. The associated variants are correlated with expression changes in response to immune stimulus at two of these genes (ITGA4 and ITGB8) and at previously implicated loci (ITGAL and ICAM1). In all four cases, the expression-increasing allele also increases disease risk. We also identified likely causal missense variants in a gene implicated in primary immune deficiency, PLCG2, and a negative regulator of inflammation, SLAMF8. Our results demonstrate that new associations at common variants continue to identify genes relevant to therapeutic target identification and prioritization.

The human genome exhibits a significant degree of invasion by viral genomes. During the course of evolution, several RNA and DNA viruses have become integrated into the vertebrate genome and there is no reason to believe that the process has ended. Integrated viral DNA may account for as much as 10% of the human genome and it is very likely that they may act as carcinogens by altering normal cellular gene expression. In this study we have compared the viral DNA sequences present in normal and tumor tissues from esophageal squamous cell carcinoma (ESCC) samples. DNA was extracted from paired normal and tumor biopsies and subjected to whole genome sequencing. Raw data run folders were converted to FASTQ files and progressed through a QC pipeline. Normal and tumor data sets were then blasted and aligned against an extensive viral sequence database using specialized DRAGEN software, so that all integrated viral DNA fragment sequences were identified. The identified viral sequences were then compared between the paired normal and tumor samples. Using this approach, a large number of viral DNA sequences were identified; these included human papilloma viruses, Herpes simplex viruses, adenoviruses and Hepatitis C viruses. Furthermore, some unexpected viruses of interest were also identified. These include the Autographa Californica Nucleopolyhedrovirus, the Emiliana Huxleyi virus 86, the Gryllus bimaculatus nudivirus and the Trichodysplasia spinulosa-associated polyomavirus, present in different tumour DNA samples. Amplification and rearrangements of endogenous retroviruses such as the Human Endogenous Retrovirus K113 were also observed. Endogenous retroviruses (ERV) can serve as long-lasting viral reservoirs and provide evidence for the coexistence between retroviruses and their hosts over many generations. Defective ERVs can also recombine to affect the expression of adjacent genes. It has been proposed that integrated viral sequences may play a possible role in the etiology and promotion of diseases such as cancer, thus targeted studies of specific viral sequences may elucidate the mechanisms of gene disruption and may ultimately lead to the development of more effective therapeutic interventions. Note: This abstract was not presented at the meeting. Citation Format: Victoria A. Patten, Lamech Mwaphaga, Christopher G. Mathew, Denver T. Hendricks, M. Iqbal Parker. Integrated viral sequences in esophageal cancer tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2572.

Background & Aims Genome-wide association studies (GWAS) have identified 140 Crohn's disease (CD) susceptibility loci. For most loci, the variants that cause disease are not known and the genes affected by these variants have not been identified. We aimed to identify variants that cause CD through detailed sequencing, genetic association, expression, and functional studies. Methods We sequenced whole exomes of 42 unrelated subjects with CD and 5 healthy subjects (controls) and then filtered single nucleotide variants by incorporating association results from meta-analyses of CD GWAS and in silico mutation effect prediction algorithms. We then genotyped 9348 subjects with CD, 2868 subjects with ulcerative colitis, and 14,567 control subjects and associated variants analyzed in functional studies using materials from subjects and controls and in vitro model systems. Results We identified rare missense mutations in PR domain-containing 1 ( PRDM1 ) and associated these with CD. These mutations increased proliferation of T cells and secretion of cytokines on activation and increased expression of the adhesion molecule L-selectin. A common CD risk allele, identified in GWAS, correlated with reduced expression of PRDM1 in ileal biopsy specimens and peripheral blood mononuclear cells (combined P = 1.6 × 10 −8 ). We identified an association between CD and a common missense variant, Val248Ala, in nuclear domain 10 protein 52 ( NDP52 ) ( P = 4.83 × 10 −9 ). We found that this variant impairs the regulatory functions of NDP52 to inhibit nuclear factor κB activation of genes that regulate inflammation and affect the stability of proteins in Toll-like receptor pathways. Conclusions We have extended the results of GWAS and provide evidence that variants in PRDM1 and NDP52 determine susceptibility to CD. PRDM1 maps adjacent to a CD interval identified in GWAS and encodes a transcription factor expressed by T and B cells. NDP52 is an adaptor protein that functions in selective autophagy of intracellular bacteria and signaling molecules, supporting the role of autophagy in the pathogenesis of CD.

Approximately 60%-80% of patients with primary sclerosing cholangitis (PSC) have concurrent ulcerative colitis (UC). Previous genome-wide association studies (GWAS) in PSC have detected a number of susceptibility loci that also show associations in UC and other immune-mediated diseases. We aimed to systematically compare genetic associations in PSC with genotype data in UC patients with the aim of detecting new susceptibility loci for PSC. We performed combined analyses of GWAS for PSC and UC comprising 392 PSC cases, 987 UC cases, and 2,977 controls and followed up top association signals in an additional 1,012 PSC cases, 4,444 UC cases, and 11,659 controls. We discovered novel genome-wide significant associations with PSC at 2q37 [rs3749171 at G-protein-coupled receptor 35 (GPR35); P = 3.0 x 10(-9) in the overall study population, combined odds ratio [OR] and 95% confidence interval [CI] of 1.39 (1.24-1.55)] and at 18q21 [rs1452787 at transcription factor 4 (TCF4); P = 2.61 x 10(-8), OR (95% CI) = 0.75 (0.68-0.83)]. In addition, several suggestive PSC associations were detected. The GPR35 rs3749171 is a missense single nucleotide polymorphism resulting in a shift from threonine to methionine. Structural modeling showed that rs3749171 is located in the third transmembrane helix of GPR35 and could possibly alter efficiency of signaling through the GPR35 receptor. Conclusion: By refining the analysis of a PSC GWAS by parallel assessments in a UC GWAS, we were able to detect two novel risk loci at genome-wide significance levels. GPR35 shows associations in both UC and PSC, whereas TCF4 represents a PSC risk locus not associated with UC. Both loci may represent previously unexplored aspects of PSC pathogenesis. (HEPATOLOGY 2013;58:1074-1083)

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access. Protein-truncating variants protective against human disease provide in vivo validation of therapeutic targets. Here we used targeted sequencing to conduct a search for protein-truncating variants conferring protection against inflammatory bowel disease exploiting knowledge of common variants associated with the same disease. Through replication genotyping and imputation we found that a predicted protein-truncating variant (rs36095412, p.R179X, genotyped in 11,148 ulcerative colitis patients and 295,446 controls, MAF=up to 0.78%) in RNF186, a single-exon ring finger E3 ligase with strong colonic expression, protects against ulcerative colitis (overall P=6.89 × 10(-7), odds ratio=0.30). We further demonstrate that the truncated protein exhibits reduced expression and altered subcellular localization, suggesting the protective mechanism may reside in the loss of an interaction or function via mislocalization and/or loss of an essential transmembrane domain. National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) DK064869 DK062432 National Human Genome Research Institute (NHGRI) DK064869 DK043351 HG005923 Crohns and Colitis Foundation 3765 Leona M. & Harry B. Helmsley Charitable Trust 2015PG-IBD001 Amgen 2013583217 CCFA 3765 Cedars-Sinai F. Widjaja Foundation, info:eu-repo/grantAgreement/EC/FP7/305479, European Union DK062413 AI067068 U54DE023789-01 Leona M. and Harry B. Helmsley Charitable Trust Crohn's and Colitis Foundation of America NIH DK062431 U01 DK062429 U01 DK062422 R01 DK092235 U01 DK062420 Medical Research Council, UK MR/J00314X/1 Wellcome Trust WT091310 098051 Inflammatory Bowel Disease Genetic Research Chair at the University of Pittsburgh PO1DK046763

Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.

Several risk factors for Crohn's disease have been identified in recent genome-wide association studies. To advance gene discovery further, we combined data from three studies on Crohn's disease ( a total of 3,230 cases and 4,829 controls) and carried out replication in 3,664 independent cases with a mixture of population-based and family-based controls. The results strongly confirm 11 previously reported loci and provide genome-wide significant evidence for 21 additional loci, including the regions containing STAT3, JAK2, ICOSLG, CDKAL1 and ITLN1. The expanded molecular understanding of the basis of this disease offers promise for informed therapeutic development.

Copy number variants (CNVs) account for a major proportion of human genetic polymorphism and have been predicted to have an important role in genetic susceptibility to common disease. To address this we undertook a large, direct genome-wide study of association between CNVs and eight common human diseases. Using a purpose-designed array we typed 19,000 individuals into distinct copy-number classes at 3,432 polymorphic CNVs, including an estimated 50% of all common CNVs larger than 500 base pairs. We identified several biological artefacts that lead to false-positive associations, including systematic CNV differences between DNAs derived from blood and cell lines. Association testing and follow-up replication analyses confirmed three loci where CNVs were associated with diseaseIRGM for Crohns disease, HLA for Crohns disease, rheumatoid arthritis and type 1 diabetes, and TSPAN8 for type 2 diabetesalthough in each case the locus had previously been identified in single nucleotide polymorphism (SNP)-based studies, reflecting our observation that most common CNVs that are well-typed on our array are well tagged by SNPs and so have been indirectly explored through SNP studies. We conclude that common CNVs that can be typed on existing platforms are unlikely to contribute greatly to the genetic basis of common human diseases. © 2010 Macmillan Publishers Limited. All rights reserved.

To identify susceptibility loci for visceral leishmaniasis, we undertook genome-wide association studies in two populations: 989 cases and 1,089 controls from India and 357 cases in 308 Brazilian families (1,970 individuals). The HLA-DRB1-HLA-DQA1 locus was the only region to show strong evidence of association in both populations. Replication at this region was undertaken in a second Indian population comprising 941 cases and 990 controls, and combined analysis across the three cohorts for rs9271858 at this locus showed P(combined) = 2.76 × 10(-17) and odds ratio (OR) = 1.41, 95% confidence interval (CI) = 1.30-1.52. A conditional analysis provided evidence for multiple associations within the HLA-DRB1-HLA-DQA1 region, and a model in which risk differed between three groups of haplotypes better explained the signal and was significant in the Indian discovery and replication cohorts. In conclusion, the HLA-DRB1-HLA-DQA1 HLA class II region contributes to visceral leishmaniasis susceptibility in India and Brazil, suggesting shared genetic risk factors for visceral leishmaniasis that cross the epidemiological divides of geography and parasite species.