These diseases are not preventable. These are conditions arising from an aberrant response from the immune system. It is also termed as an overreaction of the immune system leading to the attack of the body’s own healthy cells and tissues. Though the causes of this phenomenon is not fully understood, it is believed to be caused due to gene mutations caused by exogenous and endogenous factors. There are around 80 types of autoimmune diseases including type 1 diabetes, rheumatoid arthritis, inflammatory bowel disease, Hashimoto’s thyroiditis, psoriasis, and multiple sclerosis. Our immune system produces B cells and T cells. In autoimmunity (See: Autoimmunity), the T cell and the B cell mechanisms go awry and start attacking a specific organ’s tissues (thyroid, pancreas, etc.). This is supposed to be triggered by certain bacterial or viral infections (enterovirus), environmental factors, vitamin D deficiency, and other factors. After a genome association scan, a scan of the genes of the populations affected by various autoimmune diseases, it was found that there was a high degree of self-reactive immune response due to the presence of autoantibodies (See: Autoantibodies) and self-reactive T cells. Autoimmune diseases affect the endocrine system, blood vessels, connective tissues, skin, the blood cells, muscles, and joints. They are diagnosed by antinuclear antibody tests, autoantibody tests, C-reactive protein test, and erythrocyte sedimentation rate test (ESR). The treatment involves controlling the process of autoimmunity, reduction of symptoms, and fighting the disease.