2 FAMILIES WITH AN AUTOSOMAL-DOMINANT INHERITANCE PATTERN FOR PAPILLARY CARCINOMA OF THE THYROID

Background: Papillary carcinoma of the thyroid (PTC) is the most preva lent malignancy of the thyroid gland. Although the majority of lesions are sporadic tumors, an established relationship exists between famil ial adenomatous polyposis (FAP) and PTC. Moreover, some authors postul ate the existence of familial PTC as a distinct entity. Evidence for t his is limited, however, there being few well characterized descriptio ns of pedigrees with high prevalence of PTC. Aims: The objective of th e present study was to examine an apparent heritable predisposition to PTC occurring in two Tasmanian families in which PTC occurs commonly. Methods: Pedigree charts were constructed for both families and the m edical records of the members reviewed. Results: In Pedigree I, 7 of 2 5 members had PTC (6 of these had coexisting multinodular goiter (MNG) , and 11 others had MNG. In Pedigree II, identical male twins and thei r daughters had PTC. Conclusions: In both families there is evidence o f autosomal dominant inheritance of PTC. The association of PTC with M NG suggests a possible role for MNG in tumor pathogenesis in hereditar y PTC. The majority of the patients were diagnosed with PTC before com mencement of prospective screening, indicating clinically relevant dis ease in the families described.