RESUMO
Hereditary medullary thyroid carcinoma is inherited as an autosomal dominant trait; at birth each child of an affected parent has a 50% chance of developing the disease. Measurement of plasma calcitonin concentrations after provocative calcium or pentagastrin stimulation has proved useful in the early diagnosis of this disease. To determine the age-related risk of conversion from a negative to a positive provocative test, 445 members of 11 kindreds were studied with sequential tests. Of 159 family members with a 50% risk at birth of developing medullary thyroid carcinoma 38 converted from a negative to a positive test result (mean age of conversion was 15 years). By means of methods previously described for determining the age-related probability for developing Huntington chorea, we present a method for determining the probability of development of medullary thyroid carcinoma. An individual at risk whose test result was negative had the following probability of converting to a positive test result at a later date: age (years)/probability, 0/0.5; 5/0.49; 10/0.41; 15/0.25; 20/0.16; 25/0.10, 30/0.05; and 35/0. We conclude that hereditary medullary thyroid carcinoma is regularly detectable in the pediatric age group and that screening should begin by age 5 years and be continued at regular intervals until age 35.
Assuntos
Carcinoma/genética , Neoplasias da Glândula Tireoide/genética , Adolescente , Adulto , Fatores Etários , Calcitonina/sangue , Carcinoma/diagnóstico , Criança , Pré-Escolar , Aconselhamento Genético , Humanos , Estudos Prospectivos , Risco , Neoplasias da Glândula Tireoide/diagnósticoRESUMO
Recognition of the syndrome of OF MMN can identify individuals at risk for the early appearance of MTC. Three such patients are described. Each had the characteristic neuromas and facies, present since infancy. In each, MTC was found in childhood. In the last two patients, the diagnosis was made because of elevated serum CT concentrations. Venous drainage from the tumor, as well as tumor tissue itself, contained high levels of CT. Prompt recognition of persons with MMN is essential for proper investigation and treatment of the associated MTC.