NLRC4 and Familial cold urticaria: NLRC4-AD is an autosomal dominant autoinflammatory disease caused by mutations in the NLRC4 (NLR family CARD domain-containing protein 4) gene, and encompasses two different phenotypes: NLRC4-associated macrophage activation syndrome (NLRC4-MAS) and familial cold autoinflammatory syndrome 4 (FCAS4).