RNPC3 and systemic lupus erythematosus: Antibodies targeting small nuclear ribonucleoproteins (anti-Sm, anti-RNP) or proteins complexed with small RNAs (anti-SSA/Ro, anti-SSB/La) occur in 10–40% of SLE patients and are associated with musculoskeletal and mucocutaneous manifestations, as well as neonatal heart block [1, 2].