Predictive Genetic Testing and Genetic Counseling for Hereditary Neuromuscular Diseases in Japan: A Case Series of 40 Clients

Background With advances in genetic medicine, the number of clients considering predictive genetic testing ( PT ) for hereditary neuromuscular diseases has increased, in which genetic counseling ( GC ) plays an important role. Aim We conducted a retrospective analysis of PT and associated GC to evaluate our current GC protocol. Methods The selected subjects were those who had consulted at our department for PT and undergone at least one GC session by the end of March 2024. We extracted client background, whether genetic testing was performed, test results, and GC details. Results There were 40 clients, with a median age of 31.5 (21–62) years, and 70% in their 20s and 30s. Spinocerebellar ataxia (SCA) type 3, myotonic dystrophy type 1, and SCA31 accounted for approximately half of the cases. Twenty‐six clients did not undergo PT, among whom 16 did not continue GC, with 3 of these 16 having no key person, a source of support who also participated in GC when necessary. Of the 14 clients tested, the PT was positive in 8. Among these 14 clients, the median number of GC sessions was 4 (range: 1–6), and the median time from initial GC to PT was 15 months (range: 7–69). Conclusion In PT in our hospital, emphasis should be placed on the follow‐up of clients who withdraw from GC sessions and the handling of clients unable to take tests due to the absence of a key person. The application of prenatal testing and preimplantation testing for these diseases also needs to be considered.