Is the major histocompatibility complex linked to genes that increase susceptibility to affective disorder? A critical appraisal.

The evidence implicating genes linked to the major histocompatibility complex in the pathogenesis of affective disorder is reviewed, and 10 new multiplex families containing 26 affected siblings are presented. It is shown that when the data are properly analyzed by not dismantling multiplex sibships into all possible sib pairs, no individual data set presents compelling evidence of linkage. The present study is also negative. However, pooling all published families results in moderate evidence for nonrandom assortment.