PRTN3 and rheumatoid arthritis: For instance, a tool subclassifying individuals’ ACPA positivity and non-specific musculoskeletal symptoms and IA progression based on RA-related variables found that many individuals presented with non-specific musculoskeletal symptoms and no individuals with a low-risk score progressed to IA, while 31% of those with a moderate risk developed IA and 62% of individuals with a high risk progressed to IA [81].