Monarch Disease Ontology identifier MONDO_0012398 (achromatopsia 6) is any achromatopsia caused by a mutation in the PDE6H gene, characterized by incomplete loss of color vision, with a red-green color vision defect and normal or near-normal blue-yellow vision. Reduced visual acuity is also present, but not progressive. Also known as: ACHM6, RCD3A, retinal cone dystrophy 3A, retinal cone dystrophy type 3A.