The term autoimmune disease covers both primary myxedema (no goiter) and classic Hashimoto's disease (goiter). These are differing manifestations of the same condition. Graves disease is similar as well. Antobodies are specific proteins that everyone is born with to fight infections usually. In autoimmune disease, some antibodies, called autoantibodies, will attack the body's own organs. Autoantibodies to the TSH receptor block the physiologic effects of TSH, anti thyroid peroxidase antibodies (TPO) block the processing of thyroid hormone, and thyroid stimulating antibodies promote the production of thyroid hormone. The current understanding of autoimmune thyroiditis is thyroid cell apoptosis leading to follicular cell destruction. The thyroid gland is infiltrated by both B and T lymphocytes which are capable of destroying thyroid cells. Both Graves' disease and Hashimoto's disease can occur in the same families because there are shared genetic susceptibility genes. Your Houston Thyroid and Endocrine endocrinologists can help you understand autoimmune disease in the context of the thyroid.