Family history studies: V. The genetics of mania.

In this study of the families of 59 manic-depressive, manic type probands, the predominant affective illness among the family members was depression without mania, although mania was frequent. The findings suggest that genetic transmission occurred by a sex-linked single or double dominant gene. In two families affective disorder was linked to color blindness, implying that the X-linked gene for manic-depressive psychosis is on the short arm of the X chromosome.