LYST and arthritic joint disease: This hypothesis is corroborated by the TRIM20Δ413 structure and in fact the biological significance of the B30.2/CHS domain interface is supported by the observation that mutations that are associated with mild forms of FMF, Crohn’s disease or arthritis, such as P550A31, L649P32, S650Y and R653H33, are directly involved in this interface (Fig. 3B).