Melds genome-wide association tests with structural
equation modeling (SEM) using 'OpenMx'. This package contains
low-level C/C++ code to rapidly read genetic data encoded in U.K.
Biobank or 'plink' formats. Prebuilt modeling options include one and
two factor models. Alternately, analyses may utilize arbitrary,
user-provided SEMs. See Verhulst, Maes, & Neale (2017)