SMAD3 and rheumatoid arthritis: Other clinical characteristics that have been found to be associated to SMAD3 gene mutations include arterial tortuosity, bicuspid aortic valve (Van Der Linde et al., 2012), neurological features and immunological disorder (Aubart et al., 2014), early osteoarthritis (Van De Laar et al., 2011e Laar et al., 2011) and rheumatoid arthritis (Berthet et al., 2015).