About 30%–40% of patients with pheochromocytoma (PCC) and paraganglioma (PGL) have underlying germline mutations in certain susceptibility genes despite absent family history of these tumors. Here, we present mutational profile of 101 such patients with PCC/PGL (PPGL) from the highly consanguineous population of Saudi Arabia. Results: Of 101 cases with PPGL, 37/101 (36.6%) had germline mutations. Mutations were detected in 30 cases by PCR and direct Sanger sequencing and in 7 additional cases by NGS. The most commonly mutated gene was SDHB (21/101 cases, 20.8%) and the most common SDHB mutation was c.268C>T, p.R90X occurring in 12/21 (57%) cases. Mutations also occurred in SDHC (4/101, 3.96%), SDHD (3/101, 3%), VHL (2/101, 2%) and MAX (2/101, 2%) genes. The following genes were mutated in 1 patient each (1%), RET, SDHA, SDHAF2, TMEM127 and NF1. Metastatic PPGL occurred in 6/21 cases (28.6%) with SDHB mutations and in 1 case with SDHAF2 mutation. Patients and Methods: DNA was isolated from peripheral blood (53 patients) or from non-tumorous formalin fixed paraffin embedded (FFPE) tissue (48 patients). PCR and direct Sanger sequencing of RET, SDHx, VHL, MAX and TMEM127 genes were performed. Cases without mutations were subjected to whole exome sequencing using next generation sequencing (NGS). Conclusion: About 37% of PPGL without family history of such tumors harbor germline mutations. The most commonly mutated gene is SDHB followed by SDHC, SDHD, VHL, MAX and rarely RET, SDHA, SDHAF2, TMEM127 and NF1. SDHB mutations were associated with metastatic PPGL in more than a quarter of cases.

Non-paraganglioma (PGL) tumors are rare manifestations of familial PGL syndromes. Primary hyperparathyroidism has not been described in PGL syndromes. We present a 36-year-old man with a history of right carotid body tumor at 24 years and an abdominal PGL at 31 years of age. At 35 years, he developed hypercalcemia (serum Ca 2.65-2.72 mmol/l), and high parathyroid hormone of 92-131 ng/l (normal range, 15-65) and a Tc99 Sestamibi scan showed a single parathyroid adenoma which was confirmed on histopathological examination of parathyroidectomy. Recently, he was diagnosed with a left glomus jugulare which has not been operated on yet. His family history is strongly positive for PGLs. Genetic testing revealed a novel SDHB mutation (p.K137E) but the phenotype and penetrance were variable in different family members.