Retina and anterior neural fold homeobox 2 (RAX2), TUB like protein 1 (TULP1) and G protein subunit gamma transducin 2 (GNGT2) are associated with photoreceptor cells, with TULP1 being involved in retinitis pigmentosa [45] and RAX2 playing a role in the malignant progression of glioblastoma [46, 47]. Here, GNGT2 is linked to retinitis pigmentosa.