Blue cone monochromatism in a female due to skewed X-inactivation

Ophthalmic Genet. 2013 Mar-Jun;34(1-2):101-4. doi: 10.3109/13816810.2012.726394. Epub 2012 Sep 24.


Blue cone monochromatism (BCM) is a rare cone dystrophy with recessive X-linked inheritance and therefore diagnosed in males whereas females are clinically unaffected. We present a female with clinically manifested BCM. 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. The present case illustrates that females may develop symptoms of recessive X-linked eye diseases in rare cases.

Publication types

  • Case Reports

MeSH terms

  • Child, Preschool
  • Color Perception Tests
  • Color Vision Defects / diagnosis
  • Color Vision Defects / genetics*
  • Electroretinography
  • Female
  • Humans
  • Male
  • Pedigree
  • Point Mutation*
  • Polymerase Chain Reaction
  • Rod Opsins / genetics*
  • Tomography, Optical Coherence
  • Vision Disorders / genetics
  • Visual Acuity
  • X Chromosome Inactivation / genetics*


  • Rod Opsins
  • long-wavelength opsin
  • middle-wavelength opsin

Supplementary concepts

  • Blue cone monochromatism