Genetic linkage studies were conducted on five Old Order Amish bipolar
pedigrees in 1979 and 1982, with 94 members tested for color blindness and
typed for 42 red blood cell and related markers in 17 antigen systems.
Also, 59 individuals in two pedigrees were typed for HLA, Bf, and GLO.
Linkage analyses assuming X-linkage and autosomal inheritance of bipolar
illness were done with diagnostic schemes ranging from strict bipolar to
milder forms of affective disorder. Linkage to affective disorders was not
strongly supported for any marker locus. Close linkage to HLA was excluded,
with weaker evidence against linkage to GLO.