However, it is unknown whether ACPA are also predominant prior to the disease onset, as the data regarding AMPA reactivities in pre-RA individuals are scarce: AAPA are a very recent discovery, and their prevalence before the onset of RA (and in relationship to ACPA) has thus far been investigated in a very limited number of cohorts [14]. This evidence concerns the gene PRTN3 and rheumatoid arthritis.