Our studies suggest that similar dynamic ranges of penetrance are likely to occur for alleles associated with endocrine disease (e.g.,RET), and quantifying these is essential to enable appropriate patient care (e.g., appropriate guidance on the timing/requirement for prophylactic thyroidectomy in individuals with RET variants associated with MEN2/familial medullary thyroid cancer [27]. The gene discussed is RET; the disease is hereditary thyroid gland medullary carcinoma.