In our study, we did not observed differences regarding the age at diagnosis of metastatic disease between the group of patients with SDHB exon 1 deletion and the group of patients with sporadic PGL or PCC tumors, while a trend towards an earlier age at diagnosis of metastatic disease has been reported in patients carrying mutation in SDHx genes (especially SDHB) (Fishbein et al., 2017). This evidence concerns the gene SDHB and adrenal gland pheochromocytoma.