CDC73 and pachyonychia congenita: The identification of the main genetic driver of the hyperparathyroidism with Jaw Tumours (HPT-JT, MIM #145001) syndrome first [8] and then of familial and sporadic PC later [9], the CDC73 gene, helped in the molecular diagnosis and also in the follow up of subjects at risk to develop an aggressive parathyroid lesion, in case of familial forms.