Difficulties in disclosing secondary findings by facilities performing comprehensive germline genetic testing for rare diseases in Japan.

In Japan, a limited number of laboratories perform comprehensive genetic testing for rare diseases; this study investigated the attitudes of these laboratories toward the disclosure of secondary finding (SF). Following a preliminary survey, we identified laboratories conducting comprehensive genetic testing for participation. Subsequently, an online survey involving 20 selected facilities was conducted. The response rate was 80% (16/20). Of the 14 facilities, 71.4% had SFs. While 42.9% of them had a policy to disclose SFs with clinical utility, only 14.3% actively searched for actionable variants that could be included in the American College of Medical Genetics and Genomics list. Japan was less enthusiastic than the USA regarding SF disclosure. With regard to the reasons for not disclosing SFs, the factors "the thought that participants may have a low desire for SFs" and "uncertainty regarding their wish" were considered more important than in the USA. A content analysis of what was sought as a solution to this difficulty revealed a need to improve databases on pathogenicity and actionability and collect public thoughts on the issue. The factor "to promote entry in research" was not considered a critical reason for disclosing SFs, indicating that the thirst for information was not possibly due to anxiety but rather due to scientific interest. Japanese medical professionals may not be confident that society requires the disclosure of SFs. To improve the environment, it is necessary to survey the public regarding their thoughts on SF disclosure and discuss this issue in society.