Congenital iodine deficiency syndrome protruding abdomen. Dwarfism may also be caused by malnutrition or other hormonal deficiencies, such as insufficient growth hormone secretion, hypopituitarism, decreased secretion of growth hormone-releasing hormone, deficient growth hormone receptor activity and downstream causes, such as insulin-like growth factor 1 (IGF-1) deficiency. Sporadic and genetic congenital iodine deficiency syndrome results from abnormal development or growth of the foetal thyroid gland. This type of congenital iodine deficiency has been almost completely eliminated in developed countries by early diagnosis by newborn screening schemes followed by lifelong treatment with thyroxine (T4). Thyroxine must be dosed as tablets only, even to newborns, as the
Iodine be obtained pure. It can be synthesised from the reaction of iodine with fluorine gas in trichlorofluoromethane at −45 °C, with iodine trifluoride in trichlorofluoromethane at −78 °C, or with silver(I) fluoride at 0 °C. Iodine monochloride (ICl) and iodine monobromide (IBr), on the other hand, are moderately stable. The former, a volatile red-brown compound, was discovered independently by Joseph Louis Gay-Lussac and Humphry Davy in 1813–4 not long after the discoveries of chlorine and iodine, and it mimics the intermediate halogen bromine so well that Justus von Liebig was misled into mistaking bromine (which he had found) for iodine