Estudio del protooncogen RET en neoplasia endocrina multiple 2A y en carcinoma medular de tiroides familiar. Hallazgos clinico-patologicos en portadores asintomaticos / Study of RET protooncogene in multiple endocrine neoplasm 2A and in familial medullary thyroid carcinoma. Clinical pathological findings in asymptomatic carriers

RESUMEN

Twenty five percent of the medullary thyroid carcinoma (MTC) is hereditary and 5% is familiar (FMTC), or considered as multiple endocrine neoplasia (MEN) type 2A (17%) or 2B (3%). These diseases are the result of the autosomic dominant inheritance of a mutation in the RET protooncogene, in one out of 12 different known codons. We analyzed 7 families (2 MEN 2A and 5 FMTC). Six mutations were detected in the most frequent codon, 634 (2 MEN 2A y 4 FMTC) and one family with FMTC presented a novel mutation a transition T > C at codon 630, resulting a C630A change. Among 57 individuals studied, 25 (43.85%) presented the mutation. Seven (28%) were asymptomatic carriers, including 5 children aged 11 +/- 3.2 years. The children underwent total thyroidectomy. The histopathologic examination showed C cells hyperplasia and microcarcinoma focus in both lobes, even in the presence of normal, basal or pentagastrine stimulated, calcitonine levels. In conclusion, we describe a germine novel mutation in the RET protooncogene C630A; and the corresponding findings of C-cell disease in gene mutated carriers that emphasize the importance of prophylactic thyroidectomy as soon as the molecular diagnosis is confirmed