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 demonstrated that these animals could survive after eating a 14000 mg/kg dose). Excess iodine can be more cytotoxic in the presence of selenium deficiency. Iodine supplementation in selenium-deficient populations is, in theory, problematic, partly for this reason. The toxicity derives from its oxidizing properties, through which it denaturates proteins (including enzymes). Elemental iodine is also a skin irritant, and direct contact with skin can cause damage and solid iodine crystals should be handled with care. Solutions with high elemental iodine concentration, such as tincture of iodine and Lugol's solution, are capable of causing tissue damage if used in prolonged cleaning