Comment: Novel mutations in the OPN1LW and NR2R3 genes in a patient with blue cone monochromacy

Abstract

I was puzzled by the conclusions of the article by Cai et al. entitled “Novel mutations in the OPN1LW and NR2E3 genes in a patient with blue cone monochromacy” (1). The authors state there that “the novel mutations of c.244A>G; p.K82E in the OPN1LW gene and c.361G>A; p.E121K in the NR2E3 gene both cause blue cone monochromacy”. The NR2E3 c.361G>A; p. E121K variant was initially reported by Haider et al. in 2000 (2) and is by no means novel. Importantly, Yang et al. convincingly demonstrated several years ago that this variant is a common single nucleotide polymorphism in the Chinese population, because it was present at a comparable frequency of respectively 13.4%,10.5% and 12.8%, in a cohort of Chinese retinitis pigmentosa patients and in control subjects from Hong-Kong and Beijing (3). Furthermore, we had shown by functional assays, including transactivation and protein interaction assays, that the NR2E3-p.E121K variant protein exhibited activities similar to the wild-type protein (4). Therefore, the NR2E3 c.361G>A; p.E121K variant is most unlikely contributing to the ophthalmic phenotype of this patient, and the authors present no data in support of NR2E3 variants causing blue cone monochromacy. Funding