These include Sjögren's syndrome–related antigen A (SSA; also known as Ro), Sjögren's syndrome–related antigen B (SSB; also known as La), Smith (Sm), topoisomerase 1, ribonucleic acid (RNA) polymerase III, Jo-1 and U1 ribonucleic protein (U1RNP). This evidence concerns the gene SSB and Down syndrome.