Colorblindness-Tritanopia

Clinical Characteristics
Ocular Features: 

A selective deficiency in blue (short wavelength) spectral sensitivity is characteristic of this disorder.  Most patients retain the ability to see red and green colors although several patients with both defects have been reported.  It seems to be a stable disorder with no evidence of progressive retinal dysfunction.  ERG responses of long wavelength-sensitive cones are normal whereas those of blue-sensitive cones are undetectable.  This selectivity distinguishes tritanopia from acquired forms of color blindness such as macular disease and rod-cone dystrophies in which there is generalized dysfunction among cones.  However, there is wide variability in responses based on color vision testing suggesting that rudiments of blue-sensitive opsin function remain in some patients. 

Systemic Features: 

There are no systemic abnormalities in this disorder. 

Genetics

This is an autosomal dominant form of color blindness resulting from mutations in the OPN1SW gene located at 7q31.3-q32.  Point mutations lead to defects in the blue-sensitive opsin protein. 

Treatment
Treatment Options: 

No treatment is available.

References
Article Title: 

References

Weitz CJ, Miyake Y, Shinzato K, Montag E, Zrenner E, Went LN, Nathans J. Human tritanopia associated with two amino acid substitutions in the blue-sensitive opsin. Am J Hum Genet. 1992 Mar;50(3):498-507.

PubMedID: 1531728

Went LN, Pronk N. The genetics of tritan disturbances. Hum Genet. 1985;69(3):255-62.

PubMedID: 3872255