Table 6

Aetiology of congenital hypothyroidism

Permanent
 Thyroid dysgenesis
Thyroid agenesis
TSH
 Defective synthesis (central hypothyroidism)
 Hyporesponsiveness
 Hyper-responsiveness
Stimulating G protein deficiency
Iodide transport defect
Iodide organification defect
Thyroglobulin synthesis defect
Iodotyrosine deiodinase deficiency
Other gene defects:
Gene defect Mutation Phenotype
ThyroglobulinHomozygousMouse
Various complexGoitrous hypothyroidism
Thyroid peroxidaseHomozygous
Heterozygous
Iodide symporterHomozygousGoitre
TSH receptorHomozygousMouse
HeterozygousTSH resistance
TTF2HomozygousAthyroid
PAX8Heterozygous
Transient
Maternal antithyroid drug ingestion
Excess maternal iodide ingestion (for example, amniofetography)
TSH receptor blocking antibodies
Extreme prematurity
Transient hyperthyrotrophinaemia