GRM6 and retinoblastoma: We observed elevated expression of PI3K family genes in retinal neuron precursors, including PKI3CA, PKI3CB, PKI3CD, and PKI3CG, which was consistent with the effectiveness of PI3K‐targeted inhibitors on retinoblastoma.[38] In addition, congenital stationary night blindness (CSNB) is characterized by defects in BCs that affect the ON response of targeted photoreceptors; we observed high chromatin accessibility in the mGluR6 cascade members, including GRM6, GNB3, and GNG13 (Figure 7G), the mutations of which represent the third most common cause of complete CSNB.[39]