label: Thyroid dysgenesis
label_lc: thyroid dysgenesis
description: Thyroid dysgenesis is a descriptive term that should be avoided if more precise information is available. However, the HPO keeps retains this term because it is commonly used in the medical literature. In humans, the process of thyroid morphogenesis occurs from the 3rd to 16th week of gestation. Alterations occurring during this period may result in a thyroid gland that is absent (thyroid agenesis or athyreosis), hypoplastic (thyroid hypoplasia), or located in an unusual position (thyroid ectopy). All these entities are grouped under the term thyroid dysgenesis.