IGSF22 (immunoglobulin superfamily member 22) is a 903 amino acid protein that contains two fibronectin type-III domains and four Ig-like (immunoglobulin-like) domains, and is a member of the immunoglobulin superfamily. Members of this family of proteins usually localize to the cell membrane, and may act as receptors in immune response pathways. The gene encoding IGSF22 maps to human chromosome 11p15.1. Chromosome 11 houses over 1,400 genes, comprises nearly 4% of human genomic DNA and is considered a gene and disease association dense chromosome. The blood disorders Sickle cell anemia and thalassemia are caused by HBB gene mutations, while Wilms' tumors, WAGR syndrome and Denys-Drash syndrome are associated with mutations of the WT1 gene. Jervell and Lange-Nielsen syndrome, Jacobsen syndrome, Niemann-Pick disease, hereditary angioedema and Smith-Lemli-Opitz syndrome are also associated with defects in chromosome 11-encoded genes.