Maladaption to iodine deficiency
	Primarily this type of goitre is potentially an appropriate adaptation to iodine deficiency in that goitre formation leads to more thyroid hormone production. However, somehow the process tends to get out of control as reviewed by Dumont et al1 . A large heterogeneous goitre with large colloid filled follicles and insufficient hormone production develops in some subjects. The pathogenetic mechanisms of this lack of control are only partly known but probably activation of some of the same processes that are responsible for sporadic multinodular goitre as seen in all populations in iodine sufficient areas, are abundently operative in populations with a relatively low iodine intake.