Predisposition to autoimmune thyroiditis in ring chromosome 18 syndrome

Thyroid function was studied in five patients with ring chromosome 18 [r(18)] syndrome and in their mothers. Three of the five patients were clinically or subclinically hypothyroid and had an elevated anti-thyroid antibody (ATA) titer. Another patient had a goiter with the histology showing Hashimoto's thyroiditis. Two mothers of the five patients had an elevated ATA titer, one of whom was subclinically hypothyroid. Our findings indicate that autoimmune thyroiditis may occur with high frequency among patients with r(18) syndrome and their mothers. Thus thyroid function tests are always recommended in patients with the syndrome and their mothers.