CCHCR1 and rheumatoid arthritis: We further observed strong selection signals on chromosome 6, including MUC22, PSORS1C1, PSORS1C3, PSORS1C1|PSORS1C2, CDSN|PSORS1C1, CCHCR1, TCF19, KHDRBS2. Among them, PSORS1C1, PSORS1C3, PSORS1C1|PSORS1C2, CDSN|PSORS1C1, and CCHCR1 are genes involved in autoimmune diseases and are expressed in psoriasis, rheumatoid arthritis ankylosing spondylitis [36–38] and PSORS1C3 is also linked to major depressive disorder suicide [38].