Mutations in the GRM6 gene, which encodes mGluR6, are associated with congenital stationary night blindness (CSNB) in humans, and both human patients and mouse models in which mGluR6 is ablated exhibit a lack of b-wave in electroretinograms, indicating ON-BC disfunction (3, 18, 19, 20). Here, GRM6 is linked to breast cancer.