The causes of hypothyroidism are complex and divided into several types, but overall, hypothyroidism is not a genetic disease, some types may be affected by genetic factors, but only a high risk factor for genetic development, and does not directly inherit hypothyroidism. Among the common causes of hypothyroidism in adults are the following: autoimmune damage: the most common cause is autoimmune thyroiditis, including Hashimoto’s thyroiditis, atrophic thyroiditis, postpartum thyroiditis, etc.. Such patients have a special constitution that may be inherited, but need to be stimulated by complex external factors to develop. Thyroid destruction: This includes secondary hypothyroidism due to thyroid surgery and iodine 131 treatment. The 10-year cumulative incidence of hypothyroidism during subtotal thyroidectomy and iodine 131 treatment for Graves’ disease is 40% and 40%-70%, respectively. This category is secondary hypothyroidism and is not genetically related. Iodine overdose: Iodine overdose can cause hypothyroidism in people with underlying thyroid disease, and can also induce and aggravate autoimmune thyroiditis. The incidence of hypothyroidism induced by the iodine-containing drug amiodarone is 5%-22%. This category is mainly related to dietary habits and living environment, and is not hereditary. Anti-thyroid drugs: Anti-thyroid drugs, such as lithium salts, thioureas, and imidazoles, can also cause secondary hypothyroidism if used improperly. In addition, a number of other systemic disorders may also cause hypothyroidism, such as pituitary or hypothalamic hypofunction resulting in TRH or TSH deficiency, which can lead to central hypothyroidism. Peripheral hypothyroidism can result from reduced or defective thyroid hormone receptors in peripheral tissues, the presence of circulating antibodies to thyroid hormones, or reduced conversion of peripheral T4 to T3. There may be some genetic component to this category, but it is not clinically clear. Therefore, hypothyroidism is not a genetic disease, and even if one has a high risk of genetic development, one does not necessarily get hypothyroidism.