Because the same LACC1 mutations, p.Ile254Val and p.Cys284Arg, have been associated with multiple phenotypes including, leprosy, BD, SoJIA and early-onset CD, it is likely that environmental factors, such as microbiota, play an important role in disease expressivity and manifestations. This evidence concerns the gene LACC1 and systemic-onset juvenile idiopathic arthritis.