Germline testing of 11 PPGL susceptibility genes associated with known hereditary tumor predisposition syndromes associated with PPGLs (SDHA, SDHB, SDHC, SDHD, SDHAF2, MAX, FH, NF1, RET, TMEM127 and VHL) was done in all of these patients, in the majority of cases using a combination of targeted multi-gene sequencing with the TruSight Cancer panel (Illumina, Inc., San Diego, CA, USA) in combination with customized array-based Comparative Genomic Hybridization (array-CGH) for copy number variation (CNV) calling [24] and Sanger Sequencing of SDHA (for details see Supplementary Table S1). Here, RET is linked to cancer.