Mutations in CNGA3 (MIM#600053) [12], CNGB3 (MIM#605080) [13], GNAT2 (MIM#139340) [14], and PDE6C (MIM#600827) [13] have been detected in four probands with OT, which all encode cone phototransduction pathway proteins [13], suggesting a pathomechanistic overlap with achromatopsia (ACHM). This evidence concerns the gene GNAT2 and achromatopsia.