Germline founder variant c.1998delinsTTCT in the RET oncogene: a cohort study in 15 Belgian families.

The c.1998delinsTTCT- variant in the RET gene is pathogenic and associated with a moderate risk for medullary thyroid carcinoma and rarely with other MEN2A manifestations. Active surveillance is a possible option in heterozygous gene carriers with a negative first clinical evaluation.