Genotype imputation was carried out using IMPUTE4.0. Pre-compiled binaries for the latest version of IMPUTE4 are available at https://jmarchini.org/software/. This software is licensed free for use by researchers at academic institutions. The BGEN library source code is available at https://bitbucket.org/gavinband/bgen. BGENIE is built using this library. Pre-compiled binaries for the latest version of BGENIE are available at https://jmarchini.org/software/. This software is currently licensed free for use by researchers at academic institutions. Commercial organizations wishing to use IMPUTE4 or BGENIE must enquire about a licence from the University of Oxford.