Michèle Ramsay

Member of AWI-Gen and the H3Africa Consortium

Michèle Ramsay

Member of AWI-Gen and the H3Africa Consortium
michele.ramsay@wits.ac.za

Biography

Michèle Ramsay (PhD)
Director of the Sydney Benner Institute for Molecular Bioscience
University of the Witwatersrand, Johannesburg
Professor in human genetics and South African Research Chair holder in Genomics and Bioinformatics of African Populations.

Email:michele.ramsay@wits.ac.za

Michèle Ramsay (PhD) is the director of the Sydney Benner Institute for Molecular Bioscience at the University of the Witwatersrand, Johannesburg, professor in human genetics and South African Research Chair holder in Genomics and Bioinformatics of African Populations. As a member of the Human Heredity and Health in Africa Consortium (H3Africa) she leads the AWI-Gen study on the genetic and environmental contributions to obesity and cardiometabolic disease risk in six centres across four African countries. Her research aims to shed light on the role of African population genomic variation in susceptibility to diseases, given the ethnolinguistic and environmental diversity across the continent.

Title of the talk:Genetic and environmental contributions to obesity in African populations: the H3Africa AWI-Gen Study

Michèle Ramsay as a member of AWI-Gen and the H3Africa Consortium

Sydney Brenner Institute for Molecular Bioscience and Division of Human Genetics, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

Across Africa, the health and epidemiological transition is marked by an increase in obesity and related cardiometabolic diseases (CMDs). To identify genetic and environmental risk factors for susceptibility to common complex traits, we developed a population cross-sectional study of over 10,500 participants from six communities in four African countries (Burkina Faso, Ghana, Kenya and South Africa). Data include demography, health history, anthropometry, behavior and blood and urine biomarkers. Participants were genotyped on the newly designed Human Heredity and Health in Africa Consortium SNP genotyping array. The genotype data was enriched with imputation up to ~20 million SNPs using the Sanger Institute African imputation reference panel. Regional and sex-specific differences show that women are more likely to be obese (body mass index (BMI) >30) than men in South (42-66% vs 3-17%); East (32% vs 5%); and West Africa (1-4% vs 1-2%). The covariates associated with obesity in different regions also show clear variation, including lifestyle, behaviour and relevant biomarkers, posing analytic challenges. Furthermore, principal component analysis revealed significant population sub-structure between and within geographic regions. Increased genetic diversity and generally lower linkage disequilibrium (LD) in African populations present an advantage for fine mapping and the identification of causal variants. While revealing universal and African-specific associations with CMD-related traits these studies could enhance our understanding of the biology of obesity and related traits, including diabetes and hypertension, among Africans.