GRM6 and retinitis pigmentosa 1: Pseudodominant inheritance has already been documented in retinal disorders, including congenital stationary night blindness (CSNB) with alterations in the GRM6 gene [21], in patients with RP related to IMPG2 variants, or in cone-rod dystrophy and Stargardt disease with ABCA4 pathogenic variants [22,23].