ANTIBODIES IN THE FAMILIES OF THYROTOXIC PATIENTS

Abstract

Tests for thyroid antibodies, gastric-parietal-cell antibodies, and antinuclear factor were carried out on sera from the parents (96) and siblings (177) of 74 thyrotoxic patients and from 320 female and 191 male overtly healthy controls. The incidence of thyroglobulin and microsomal antibodies in the 57 mothers and 101 sisters of the probands was significantly higher than in controls matched for age and sex. A similar trend was found in fathers and brothers but this proved statistically non-significant. The results suggest a relationship within families of the liability to form thyroid antibodies and the propensity to develop thyrotoxicosis. The explanation may be that the propensity to develop thyroid antibodies is genetically determined and that this is a factor in the pathogenesis of thyrotoxicosis. As low levels of thyroid antibodies, however, are not uncommon in ostensibly healthy subjects there must be other factors which determine the development of thyrotoxicosis. Gastric-parietal-cell antibody was found in 19·3% of mothers of probands and this supports the concept that pernicious anæmia, thyrotoxicosis and Hashimoto's thyroiditis are ætiologically related. No unusual incidence of antinuclear factor was found in the families.