A collaborative study of genetic linkage of bipolar manic-depressive illness and red/green colorblindness. A project of the biological psychiatry collaborative program of the world health organization.

A study of linkage of bipolar manic-depressive illness to the protan/deutan colorblindness region of the X-chromosome was performed on 16 informative families, in a WHO collaborative study (eight families from Brussels, Six from Bethesda, one each from Basel and Copenhagen). Overall, the series did not support close linkage, but is possibly suggestive of loose linkage. The possibility of genetic heterogeneity of bipolar manic-depressive illness, with one form linked to colorblindness, is considered.