Thyroid Dyshormonogenesis 4, also known as iodotyrosine dehalogenase deficiency, is related to hyperthyroxinemia, euthyroid, caused by generalized 5-prime-deiodinase deficiency and hypothyroidism. An important gene associated with Thyroid Dyshormonogenesis 4 is IYD (Iodotyrosine Deiodinase), and among its related pathways/superpathways are Thyroid hormones production and peripheral downstream signaling effects and Metabolism of amine-derived hormones. Affiliated tissues include thyroid and bone, and related phenotypes are intellectual disability and hypothyroidism