Abstract
Genetic predisposition to Hashimoto's thyroiditis is suggested by its striking aggregation in families and its occurrence in twins. The manifestations range from overt clinical and biochemical hypothyroidism to the detection of thyroid autoantibodies in healthy, symptom-free individuals and their relatives. So far as the authors are aware, the finding of Hashimoto's thyroiditis in identical triplets has not previously been reported and they therefore present the cases of Faith, Hope and Charity, 63-year-old triplet sisters.