Article Sections

Introduction

Congenital hypothyroidism is characterized by insufficient thyroid hormone at birth.  It is one of the most common preventable causes of growth failure and intellectual disability.  Early detection and treatment are essential for normal physical and cognitive development.

Pathogenesis and risk factors

Congenital hypothyroidism can be permanent or transient.  Permanent congenital hypothyroidism most commonly occurs due to primary hypothyroidism (most common) or secondary (central) hypothyroidism.

Primary hypothyroidism

Primary hypothyroism is characterized by insufficient thyroid hormone secretion by the thyroid gland due to thyroid dysgenesis (most common), thyroid dyshormonogenesis, or thyroid hormone-stimulating hormone resistance, as follows:

  • Thyroid dysgenesis
    • Ectopy:  In early gestation, the thyroid diverticulum forms in the primitive pharynx and descends to the anterior neck ( Figure 1), remaining attached to the tongue by the thyroglossal duct.  When this process is disrupted (due to a genetic mutation), the thyroid gland can be located anywhere along the thyroglossal duct, resulting in ectopic thyroid tissue that does not secrete sufficient thyroid hormone.

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