DUOXA2 and hypothyroidism: Iodine deficiencyMaternal/foetal exposure to excess iodineTransplacental transfer of TSH-R blocking antibodies from the motherMaternal and foetal iodine deficiencyPerinatal acute illnessCongenital liver haemangioma (consumptive hypothyroidism due to excess type 3 de-iodinases)Downs syndromeHeterozygous THOX-2 and DUOXA2 mutations