Japanese Public Health Insurance System's new genomic strategic action to shorten the "diagnostic odyssey" for patients with rare and intractable diseases.

In June 2024, the Japanese government introduced a new genomic strategic action to shorten the "diagnostic odyssey" for patients with rare and intractable diseases: Six groups of rare diseases, (i) Muscle weakness group, (ii) Growth retardation, intellectual disability, and characteristic facial features group, (iii) Intellectual disability/epilepsy group, (iv) Cardiomyopathy group (mainly adult onset) (v) Proteinuria group, (vi) Fever, inflammation, skin rash, osteoarthritis group, have been newly recognized as "difficult-to-differentiate disorders" and comprehensive genomic testing can be reimbursed when patients belong to one of the six groups and certain requirements are met. The introduction of comprehensive genomic testing will improve the diagnosis rate of diseases and have significant potential to enhance Japan's rare and intractable disease policy. The new strategy in Japan and its rationale will be a reference for insurance reimbursement of comprehensive genomic testing in other countries that have universal health coverage supported by the public health insurance system.