Repository logo
 

Within-sibship genome-wide association analyses decrease bias in estimates of direct genetic effects.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Abstract

Estimates from genome-wide association studies (GWAS) of unrelated individuals capture effects of inherited variation (direct effects), demography (population stratification, assortative mating) and relatives (indirect genetic effects). Family-based GWAS designs can control for demographic and indirect genetic effects, but large-scale family datasets have been lacking. We combined data from 178,086 siblings from 19 cohorts to generate population (between-family) and within-sibship (within-family) GWAS estimates for 25 phenotypes. Within-sibship GWAS estimates were smaller than population estimates for height, educational attainment, age at first birth, number of children, cognitive ability, depressive symptoms and smoking. Some differences were observed in downstream SNP heritability, genetic correlations and Mendelian randomization analyses. For example, the within-sibship genetic correlation between educational attainment and body mass index attenuated towards zero. In contrast, analyses of most molecular phenotypes (for example, low-density lipoprotein-cholesterol) were generally consistent. We also found within-sibship evidence of polygenic adaptation on taller height. Here, we illustrate the importance of family-based GWAS data for phenotypes influenced by demographic and indirect genetic effects.

Description

Funder: Jacobs Foundation

Keywords

Genome-Wide Association Study, Humans, Mendelian Randomization Analysis, Multifactorial Inheritance, Phenotype, Polymorphism, Single Nucleotide

Journal Title

Nat Genet

Conference Name

Journal ISSN

1061-4036
1546-1718

Volume Title

54

Publisher

Springer Science and Business Media LLC
Sponsorship
Medical Research Council (MC_UU_00011, MC_UU_00007/10)
RCUK | MRC | Medical Research Foundation (MC_UU_00011)
RCUK | Medical Research Council (MC_UU_00011)
Wellcome Trust (208806/Z/17/Z)