MAX and pheochromocytoma: Recent studies have indicated that up to 40% of pheochromocytomas could be attributable to an inherited germline variant in an increasing list of susceptibility genes (6), which can be grouped into three clusters: pseudohypoxia group (VHL, SDHA, SDHB, SDHC, SDHD, SDHAF2, FH and EPAS1), kinase signalling group (RET, NF1, TMEM127, MAX and HRAS) and Wnt signalling group (CSDE1 and MAML3) (7).