Indeed, recent exome sequencing initiatives published during the finishing of this work have revealed additional genes, including ATRX, MDH2, and KMT2D, to be potentially involved in PCC/PGL pathogenesis [5, 6, 39, 40], and FGFR1 can now be added to the list of PCC susceptibility genes. Here, MDH2 is linked to adrenal gland pheochromocytoma.