Anti-NXP-2 has, as its target, NXP-2 and occurs in 15–22% of the children with JDM; it is associated with calcinosis, especially in children diagnosed below the age of 5 years [57] who manifest more severe muscle disease and gastrointestinal bleeding, resulting in a worse disease outcome with a lower functional status [58]. Here, MORC3 is linked to calcinosis.