Table 2.

Joint Susceptibility Genes for T1D and AITD

Gene	Chromosome	Function
Confirmed joint susceptibility genes
HLA class II genes	6	Presents autoantigens to T cells
PTPN22	1	Negatively influences T cell receptor signaling pathway
CTLA-4	2	Suppresses T cell activation
FOXP3	X	Controls differentiation of regulatory T cells
Candidate susceptibility genes
IL-1RA	2	Implicated in pathogenesis of autoimmune diseases
IL-4	5	Implicated in Th2 humoral immunity
MICA	6	NKG2D receptors stimulate NK cells and T cell effector functions
TNF-α	6	Implicated in pathogenesis of autoimmune diseases
Tg	8	Represents a major target of the immune response in AITD
IL2RA/CD25	10	Impacts production and function of regulatory T cells
VNTR (insulin)	11	Alters transcription of the insulin gene
ERBB3	12	Not defined
CLEC16A	16	Implicated in pathogen recognition
CD40	20	Interacts with CD40 ligand on T cells

Abbreviations: CD40, B cell–associated molecule CD40; CLEC16A, C-type lectin domain family 16 member A; ERBB3, v-erb-b2 erythroblast leukemia viral oncogene homolog 3; IL-1RA, IL-1 receptor antagonist; IL2RA, IL-2Rα; MICA, MHC class I chain-related gene A; NK, natural killer; NKG2, NK cell group 2 (group of genes that are expressed primarily in NK cells encoding a family of C-type lectins; the NKG2D gene is expressed as a major 1.8-kb and a minor 3.2-kb transcript in NK cell lines and in some T cell lines); Tg, thyroglobulin; VNTR (insulin), insulin gene variable number of an 86-tandem repeat [a penta-allelic 86-bp tandem repeat (VNTR) occurs in intron 2, of which allele 2 (IL1RN*2) is associated with autoimmune conditions].