MEN1 and pachyonychia congenita: 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).