TG and vitamin D deficiency: Predisposing genes are human leukocyte antigen (HLA), cytotoxic T lymphocyte antigen-4 (CTLA-4), protein thyrosin phosphatase non-receptor type 22 (PTPN22) and thyroglobulin (Tg) genes.2 In recent years, vitamin D deficiency is reported to cause autoimmune diseases.