Revisiting the genotype-phenotype correlation in children with medullary thyroid carcinoma: A report from the GPOH-MET registry.

Identification of children carrying de novo RET M918T mutations by means of the characteristic phenotype is crucial to detect MTC at an early stage, which will be associated with improved survival. As calcitonin levels may be false-negative and modest-risk mutation carriers present with a variable phenotype, particular attention should be paid to these children.