Mutually exclusive mutations in DAXX (death domain-associated protein) and ATRX (Alfa-talasemia or mental retardation syndrome X-linked) were initially described by Jiao et al. in 45% of P-NETs (n = 68) [37], and later validated in the whole genome sequencing study conducted by Scarpa et al. (n = 102) [38]. Here, DAXX is linked to X-linked syndromic intellectual disability.