Failure to demonstrate parent-of-origin effect in transmission of bipolar II disorder

Background: Parent-of-origin effect (POE) is suggested in transmission of bipolar disorder. Bipolar II disorder (BPII) should be considered separately. Methods: The gender difference of transmitting parents, prevalence rate in children, and age at onset of patients in relation to the sex of the transmitting parent, were examined in 220 BPII patients. Results: No evidence suggesting involvement of POE was found. Conclusion: POE is not involved in transmission of BPII. Limitation: Number of subjects is not sufficient. Rate of interviewed subjects differs between mothers and fathers. Clinical relevance: Female BPII patients do not transmit the disease more often than male patients. (C) 1998 Elsevier Science B.V. All rights reserved.