Introduction. The multiple endocrine neoplasia type 2A (MEN 2A) syndrome,
comprising medullary thyroid carcinoma (MTC), pheochromocytoma and primary
hyperparathyroidism (PHPT) is most frequently caused by codon 634 activating
mutations of the RET (rearranged during transfection) proto-oncogene on
chromosome 10. For this codon-mutation carriers, earlier thyroidectomy
(before the age of 5 years) would be advantageous in limiting the potential
for the development of MTC as well as parathyroid adenomas. Case Outline.
This is a case report of 3-year-old boy from the MEN 2A family (the boy?s
father and grandmother and paternal aunt) in which cysteine substitutes for
phenylalanine at codon 634 in exon 11 of the RET proto-oncogene, who
underwent thyroidectomy solely on the basis of genetic information. A boy had
no thyromegaly, thyroidal irregularities or lymphadenopathy and no
abnormality on the neck ultrasound examination. The pathology finding of
thyroid gland was negative for MTC. Two years after total thyroidectomy,
5-year-old boy is healthy with permanent thyroxine replacement. His serum
calcitonin level is <2 pg/ml (normal <13 pg/ml), has normal serum calcium and
parathyroid hormone levels and negative urinary catecholamines. Long-term
follow-up of this patient is required to determine whether very early
thyroidectomy improves the long-term outcome of PHPT. Conclusion. Children
with familial antecedents of MEN 2A should be genetically studied for the
purpose of determining the risk of MTC and assessing the possibilities of
making prophylactic thyroidectomy before the age of 5 years.