Investigation through Whole Genome Sequencing revealed that he had no pathogenic or likely-pathogenic variants in both alleles of the MIF gene or in genes associated with monogenic arthritis (LACC1, LPIN2, MAFB, NFIL3, NOD2, PRG4, PRF1, STX11, TNFAIP3, TRHR, UNC13DI). This evidence concerns the gene PRF1 and arthritic joint disease.