The diagnosis was genetically verified with the identification of one single red-green OPN1LW/MW hybrid gene harboring a point mutation c.607C>G, p.Cys203Arg that associates with BCM and in addition a completely biased X-inactivation in DNA isolated from full blood and buccal mucosa.
In contrast, subjects with the C203R missense mutation presented with congenital blue cone monochromacy, with retinal lamination defects being restricted to the ONL+HFL and the degree of residual cone structure (8% of normal) being consistent with that expected for the S-cone submosaic.
Genetic analysis identified the presence of novel double heterozygous of c.361G>A; p.E121K in NR2E3, a gene responsible for enhanced S-cone syndrome (ESCS; OMIM #268100) and c.244A>G; p.K82E in OPN1LW, a gene responsible for blue cone monochromacy (BCM; OMIM#303700).
Genetic analysis identified the presence of novel double heterozygous of c.361G>A; p.E121K in NR2E3, a gene responsible for enhanced S-cone syndrome (ESCS; OMIM #268100) and c.244A>G; p.K82E in OPN1LW, a gene responsible for blue cone monochromacy (BCM; OMIM#303700).
Individuals with LCR deletions or p.Cys203Arg mutations were more likely to have nystagmus and poor vision, with disease progression in some p.Cys203Arg patients.
Individuals with LCR deletions or p.Cys203Arg mutations were more likely to have nystagmus and poor vision, with disease progression in some p.Cys203Arg patients.