ATRX and Alpha-thalassemia: In sporadic (i.e. non-familial) PNETs, inactivating mutations in MEN1, alpha thalassemia/mental retardation syndrome x-linked (ATRX) chromatin remodeller (ATRX), and death domain-associated protein (DAXX) are the most common, occurring in up to 40% of PNETs, and are involved in epigenetic regulation (Jiao et al. 2011, Thakker 2014, Chan et al. 2018) and inhibition of proliferative pathways (Jiao et al. 2011, Chamberlain et al. 2014).