Comprehensive genome analysis may reveal secondary findings (SFs) including pathogenic variants of genes other than those originally targeted. Comprehensive genetic analysis of rare diseases is generally performed as research in Japan. Therefore, the status and difficulties in SF disclosure remain unclear. To obtain information for the appropriate disclosure of SFs in rare diseases, we conducted a survey on how SFs are handled in clinical practice by facilities that outsource comprehensive genetic testing to other facilities. The response rate was 66.7% (40/60). Among the responding facilities, 55% had a policy of disclosing SFs with clinical utility and considered targeting actionable SFs with high penetrance. These facilities had difficulties in determining the disclosure targets (51%) and in genetic counseling (38%). Improving genetic literacy, establishment of surveillance systems, and providing insurance coverage for medical care to unaffected carriers were commonly cited as solutions to these difficulties. A comparison of the willingness to disclose SFs between overseas and in Japan showed more reluctance in Japan (86% vs. 65% for actionable SFs and 62% vs. 16% for non-actionable SFs). The group with difficulty in determining disclosure targets was significantly more likely to discuss this at conferences with other facilities and to refer guidelines. This suggests that the group with difficulties was unable to make decisions solely at their own facility and sought collaboration with other facilities. These findings suggest the necessity for a system that allows consultation with experts across facilities and guidelines that set forth policies for determining SFs.
© 2022. The Author(s), under exclusive licence to The Japan Society of Human Genetics.