X-Linked Dominant Manic-Depressive Illness: Linkage with Xg Blood Group, Red-Green Color Blindness, and Vitamin B12 Deficiency

Some of the literature describing X-linked dominant manic-depressive illness is reviewed. A family with manic-depressive illness, red green color blindness, Xg blood group, and vitamin B12 deficiency, all located on the same X chromosome through four generations, is described. In the family studied the gene for manicdepressive illness and the gene for vitamin B-12 deficiency occupy the same locus, and it is proposed that the X-linked manic-depressive illness is very much associated with an X-linked metabolic disturbance resulting in vitamin B-12 deficiency. The data very much support previous findings that manic-depressive illness can be sex-linked dominant and that bipolar and unipolar illness within the same family are genetically related and express the same genotype.