MEN1 and hyperparathyroidism: While PHPT is a cardinal feature of hyperparathyroidism-jaw tumor syndrome [67] and it is the main manifestation of MEN1, affecting over 90% of patients [68], the prevalence of PHPT in MEN2 is lower, with a penetrance around 30% (e.g., recent data reported a prevalence of up to 31.3% [45], as identified across our analysis).