The hereditary syndromes associated with PC include the hyperparathyroidism‐jaw tumor (HPT‐JT) syndrome, the multiple endocrine neoplasia (MEN) type 1 (MEN1) and type 2 (MEN2) syndromes, and potentially the non‐syndromic familial isolated primary hyperparathyroidism (FIHP), which may be clinically difficult to distinguish from the MEN1 and HPT‐JT syndromes (Figure 1). This evidence concerns the gene MEN1 and multiple endocrine neoplasia type 1.