Although the precise etiology has not been elucidated, there is a general consensus that type 1 diabetes is mainly a T‐cell‐mediated disease triggered by environmental factors with subsequent defects in β‐cell antigen‐specific immune tolerance and destructive lymphocytic infiltration into islets producing C‐X‐C motif chemokine 10 (CXCL10). The gene discussed is CXCL10; the disease is type 1 diabetes mellitus.