Endemic Cretinism in Idjwi Island (Kivu Lake, Republic of the Congo)

Endemic cretins comprise 1.1% of the population of the northern half of Idjwi Island (Kivu Lake, Republic of the Congo). Goiter is common in this part of the island, whereas no cretin was found in the southwest of the island where goiter is much less prevalent. Ninety percent of the cretins are hypothyroid with severe growth and mental retardation, incomplete maturation of the features, myxedematous thickened dry scaly skin, and markedly delayed sexual development. Only 10% of the Idjwi cretins are clinically euthyroid, and most of those are deaf-mute and spastic. Studies on 21 typical myxedematous cretins showed lower 131I uptake and PBI than euthyroid controls from the same area, marked retardation in bone maturation, epiphyseal and metaphyseal dysgenesis and failure of modeling. The bone changes were consistent with hypothyroidism appearing by birth or during the first months of life. Electrocardiograms showed low voltages of the QRS complexes and T waves. Extremely high blood TSH levels indicated primary hypothyroidism. Thyroid scannings showed small glands in normal position. Some showed nonhomogeneous localization of the radioiodine suggesting a degenerative process. Thus, most of the cretins in the Idjwi goiter endemia are myxedematous, possibly as a result of a degenerative process of the thyroid gland occuring by birth or in early infancy. The cause of this phenomenon is unknown.