PARENT-OF-ORIGIN EFFECT IN TRANSMISSION OF BIPOLAR DISORDER

Recently, possible involvement of a parent-of-origin effect in the tra nsmission of bipolar disorder has been suggested. We examined the poss ible contribution of parent-of-origin effect by using data from a larg e family and family history study of bipolar patients in the Collabora tive Depression Study In 276 probands with bipolar I disorder; family histories were examined using three diagnostic criteria: 1) bipolar I disorder, 2) bipolar I or bipolar II disorder, and 3) bipolar disorder s or recurrent unipolar depression for parents and siblings. An excess of affected mothers was not observed when unipolar depression was exc luded. Age-at-onset was significantly lower in probands having a fathe r with bipolar disorders or recurrent unipolar depression than in prob ands with an affected mother: This difference was not observed when un ipolar depression was excluded. There was no significant difference of prevalence rate in children of affected mothers and those with affect ed fathers. These data do not support the contribution of parent-of-or igin effect in the transmission of bipolar disorder. (C) 1996 Wiley-Li ss, Inc.