Endemic Goitre in Greece: Family Studies.

The evidence implicating iodine deficiency in the aetiology of endemic goitre is overwhelming, and a deficiency of iodine in the diet has been accepted as the main cause of this condition (Kelly and Snedden, I960; Greer, I962; Wayne, Koutras, and Alexander, I964). Considerations of the quantitative aspects of iodine metabolism leave little doubt that in the presence of a sufficiently severe and prolonged iodine deficiency the development of goitre is an obligatory response if the individual is to remain euthyroid (Riggs, I952). Nevertheless, it is an old observation that in most endemic areas all the inhabitants are not similarly affected, and that villages with and without endemic goitre may be situated the one near the other, sharing presumably similar food supplies. It is, therefore, probable that when the environmental iodine deficiency is not unusually severe, only certain predisposed individuals may develop a goitre, whereas others similarly exposed do not do so. It has been suggested that in certain cases endemic goitre might be the result of a mild environmental iodine deficiency playing upon a genetic abnormality commonly present in the inhabitants of the community concerned (Stanbury, ig6oa). Even Curtis and Fertman (I949) noted that residence for 6 months in the Yunnan district sufficed to induce goitre in 'susceptible' persons, thus distinguishing between more and less susceptible subjects. The familial factor in simple goitre is obvious in the rare cases of sporadic goitre due to a clearly defined inborn error of iodine metabolism (Stanbury, ig6ob), whereas in the endemic goitre areas of Switzerland monozygotic twins did not show any more concordance with respect to goitre than did dizygotic ones (Eugster, I934). Obviously when the environmental factor is very potent a possible familial predisposition is overshadowed. In London, however, I34 patients with non-toxic nodular goitre showed a proportion of 4I % of non-tasters for phenylthiourea compared to-avalue of 31I2 % derived from normal controls (Harris, Kalmus, and Trotter, I949), and these results have been confirmed by Kitchin, Howel-Evans, Clarke, McConnell, and Sheppard (I959). In a goitre survey in the Vale of Glamorgan (South Wales), relatives of goitrous patients showed a higher prevalence of goitre than relatives of a control group matched for age and sex (Trotter, Cochrane, Benjamin, Miall, and Exley, I962). In the same study, goitrous patients appeared to consume less fish than the controls, thus supporting the view that dietary and familial factors may both be important. In many areas of Greece simple goitre is endemic (Hadjidakis, 1959). In these areas many families are obviously more affected than other ones in the same village, and this has prompted the present study, involving the physical examination and the construction of family trees of all the inhabitants of seven villages in the goitre area.