We compared TP53 isoform expression in RA synovia with that in OA and found levels of TP53 isoform mRNA vary, with ~ 100-fold more expression of the TP53β and FL/Δ40TP53_T2 mRNAs than of FL/Δ40TP53_T1, Δ133TP53 and TP53β mRNAs (Additional file 1: Fig. S4). The gene discussed is TP53; the disease is rheumatoid arthritis.