Dysfunction of the thyrotropic axis and congenital hypothyroidism

Thyrotropic dysfunctions are divided into :

• a primary abnormality in TRH/TSH production

Congenital hypothyroidism of central origin is rare and often diagnosed late due to normal TSH levels. Earlier screening for genetic causes will improve cognitive development.

• an abnormality in the regulation of TSH and TRH, including resistance to thyroid hormones (RTH)

A biological picture of High T4 and/or T3 and normal or elevated TSH has been described with variants of the TR β, TRα and MCT8 genes, but also in cases of artefacts in dosage linked to variants of thyroid hormone-binding proteins. Diagnosing true TSH resistance is difficult and there are many diagnostic errors.

• a non-autoimmune disorder affecting the peripheral production of thyroid hormones (congenital hypothyroidism, or familial adult-onset hypothyroidism, non-autoimmune hyperthyroidism, etc.)