[Sipple's syndrome. Review of the literature and personal case load]

A family with Sipple's syndrome was studied over three generations. The syndrome is transmitted as a dominant autosomic hereditary trait with high penetrance and varying expressiveness. Our series include 13 patients of three generations: 1) husband and wife who were 1st degree cousins; 2) 4 sisters and 1 brother; 3) 5 sisters and 1 brother. In the first generation we did not find any sign that could be related to the syndrome, in the second generation 2 thyroid carcinomas and a pheochromocytoma were present, and in the third one 2 sisters had these neoplasias, one pheochromocytoma and the other thyroid cancer, another one had marfanoid habitus and the fourth one had pheochromocytoma. This series includes 11 subjects of the second and third generation; the Sipple's syndrome was present in 7 females. The incidence of the syndrome was 63.8% and present only in female subjects. The high incidence rate could be caused by the strict relation between the grandparents. The diffusion of this pathology may be related to the high penetrance of the gene(s) involved whereas the clinical variations may be interpreted to the variable expressiveness and, even more so, as evidence that the other manifestations of the syndrome may occur later in time.