I think it suggests that the blindness comes from a different, rarer variant (in the PROM1 gene). If anything that would update me towards thinking the IQ effect, if real, also comes from that rarer variant.
(Edit: the 6 carriers of the PROM1 mutation studied in this paper had an average verbal IQ of 104, which is pretty strong evidence against it giving a huge boost to verbal IQ as reported by the CORD7 paper).
I think it suggests that the blindness comes from a different, rarer variant (in the PROM1 gene). If anything that would update me towards thinking the IQ effect, if real, also comes from that rarer variant.
(Edit: the 6 carriers of the PROM1 mutation studied in this paper had an average verbal IQ of 104, which is pretty strong evidence against it giving a huge boost to verbal IQ as reported by the CORD7 paper).