A genome‐wide association study‐derived polygenic score for interleukin‐1β is associated with hippocampal volume in two samples

IntroductionMany diseases of adulthood are associated with a woman’s age at menarche. Genetic variation affects age at menarche, but it remains unclear whether in women of African ancestry the timing of menarche is regulated by genetic variants that were identified in predominantly European and East Asian populations.MethodsWe explored the genetic architecture of age at menarche in 3145 women of African ancestry who live in the USA, Barbados and Nigeria. We undertook a genome-wide association study, and evaluated the performance of previously identified variants.ResultsOne variant was associated with age at menarche, a deletion at chromosome 2 (chr2:207216165) (p=1.14×10−8). 349 genotyped variants overlapped with these identified in populations of non-African ancestry; these replicated weakly, with 51.9% having concordant directions of effect. However, collectively, a polygenic score constructed of those previous variants was suggestively associated with age at menarche (beta=0.288 years; p=0.041). Further, this association was strong in women enrolled in the USA and Barbados (beta=0.445 years, p=0.008), but not in Nigerian women (beta=0.052 years; p=0.83).DiscussionThis study suggests that in women of African ancestry the genetic drivers of age at menarche may differ from those identified in populations of non-African ancestry, and that these differences are more pronounced in women living in Nigeria, although some associated trait loci may be shared across populations. This highlights the need for well-powered ancestry-specific genetic studies to fully characterise the genetic influences of age at menarche.

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A GWAS-Derived Polygenic Score for Interleukin-1β is Associated with Hippocampal Volume in Two Samples

10.1101/516989 ◽

2019 ◽

Author(s):

Reut Avinun ◽

Adam Nevo ◽

Annchen R. Knodt ◽

Maxwell L. Elliott ◽

Ahmad R. Hariri

Keyword(s):

Genome Wide Association Study ◽

Positive Association ◽

Hippocampal Volume ◽

Imaging Genetics ◽

Interleukin 1Β ◽

Polygenic Score ◽

Genome Wide ◽

Polygenic Scores ◽

Two Samples ◽

The Uk

AbstractAccumulating research suggests that the pro-inflammatory cytokine interleukin-1β (IL-1β) has a modulatory effect on the hippocampus, a brain structure important for learning and memory as well as linked with both psychiatric and neurodegenerative disorders. Here, we use an imaging genetics strategy to test an association between an IL-1β polygenic score, derived from summary statistics of a recent genome-wide association study (GWAS) of circulating cytokines, and hippocampal volume, in two independent samples. In the first sample of 512 non-Hispanic Caucasian university students (274 women, mean age 19.78 ± 1.24 years) from the Duke Neurogenetics Study, we identified a significant positive correlation between higher polygenic scores, which presumably reflect higher circulating IL-1β levels, and average hippocampal volume. This positive association was successfully replicated in a second sample of 7,960 white British volunteers (4,158 women, mean age 62.63±7.45 years) from the UK Biobank. Collectively, our results suggest that a functional GWAS-derived score of IL-1β blood circulating levels affects hippocampal volume, and lend further support in humans, to the link between IL-1β and the structure of the hippocampus.

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