Two polymorphisms of the EZH2 gene were identified with different prevalence: the rs2072407 variant was present in the 30 % of the samples, in keeping with the overall frequency in larger populations, while the rs78589034 variant, located close to the 5' end of the exon 16, was detected in only one proband with familial isolated hyperparathyroidism; we investigated the possible outcome on the splicing process.