Researchers at Weill Cornell Medicine – Qatar (WCM-Q) are helping shine a light on traits that are associated with various degrees of consanguineous marriage.

With funding from the Biomedical Research Program at WCM-Q, Dr Steven C Hunt, professor of genetic medicine, and Dr Noha A Yousri, adjunct assistant professor of research in genetic medicine, participated in a large meta-analysis with hundreds of scientists from across the globe, studying genetic variations in more than 1.4 million individuals.

Dr Noha Yousri
Dr Noha Yousri
Dr Steven Hunt
Dr Steven Hunt

According to Dr Yousri, very large numbers of samples are required to study the impact of marriage between men and women from the same extended families.

The study conducted a meta-analysis of results from 119 independent cohorts to quantify the effect of consanguineous marriages on 45 commonly measured complex traits of biomedical or evolutionary importance, and an additional 55 more rarely measured traits included in the UK Biobank. Complex traits were arranged into 16 groups covering major organ systems and disease risk factors were analysed.

Genetic associations with 32 of 100 studied traits and conditions in humans were identified by using runs of homozygosity (ROH). ROH refers to long continuous segments of identical alleles (homozygosity) along both inherited chromosomes. ROH arise through consanguineous marriages, i.e. when both parents are related through a common ancestor. The net directional effect of all recessive variants on traits is quantified and related to 100 traits and conditions.

Dr Hunt said runs of rare recessive variants inherited through these types of unions were shown to reduce reproductive fitness or fertility, with a 55% reduction in the odds of having children. ROH were also associated with decreased height, increased waist to hip ratio, decreased lung function, and reduced educational attainment.

The most important aspect of this study, according to Dr Yousri, is finding the traits affected by consanguineous marriages.

Given that this type of marriage is relatively common in Qatar, it would be beneficial to investigate whether those results might apply to Qatar, as it might help us better understand the implications.

The full study, which was led by Professor James F Wilson and his group from the University of Edinburgh, has been published in the high impact journal Nature Communications. Follow this LINK to read the published research.

Dr Yousri is also collaborating with Sidra Medicine on a related study called ‘The PMED-Qatar Study: Personalized Molecular Evaluation and Diagnosis for Rare Diseases in Qatar’, funded by Qatar National Research Fund.

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