IFNA1 and systemic lupus erythematosus: Toll-like receptor (TLR)7 dysregulation through defective X chromosome inactivation and resulting bi-allelic gene expression in women [45], TLR7 duplication [46], common gene variants affecting gene expression [47–50], IFN gene: gene epistasis involving TLR7 polymorphisms [51], and/or TLR7 variants affecting transcript stability [52] has been linked with SLE.