PRL and Increased circulating prolactin concentration: The Asp187Glu variant lies close to the PRL binding site and is predicted to lose contact with the adjacent His188 residue, which has a critical role in ligand binding (Kulkarni et al. 2010) and is mutated in some individuals with hyperprolactinaemia (Newey et al. 2013) (Fig. 2E, Table 1).