NOTCH4 and psoriatic arthritis: Moreover, the mapped gene NOTCH4 is one of the most important genes reported to be associated with multiple diseases in the disease category of the musculoskeletal system and connective tissue, such as rheumatoid arthritis (M06.9) [56], psoriatic arthritis (M07.3) [57], Takayasu arteritis (M31.4) [58], systemic lupus erythematosus (M32.9) [59], and appendicular lean mass (M62.9) [60].