Description of a SDHD c.129G>A (p.W43X) Mutation With Variable Presentation in Multiple Family Members

Approximately 40% of paragangliomas and pheochromocytomas are attributed to hereditary mutations. SDHD mutations account for 7% of inherited mutations (PGL1 syndrome), is maternally imprinted and has variable penetrance. SDHD pathogenic variants (PV) have been previously described extensively in Dutch pedigrees, with a varying lifetime risk for tumor development. Here we report a large family (Fig 1) displaying a SDHD c.129G>A (p.W43X) variation in 12 family members, 10 of whom had screening or tumor history available. The presentation and age of diagnosis in family members showed variable penetrance. Age at first diagnosis of a pheochromocytoma/paraganglioma ranged from 10 - 45 years. Family members displayed bilateral pheochromocytomas, bilateral carotid body tumors, and paragangliomas of the head, neck and trunk with variable recurrence rates (none to multiple). No malignant lesions were detected to date. Pheochromocytomas were norepinephrine producing. Paragangliomas ranged from non-functional to dopamine and norepinephrine producing. Compared to previous reports of other SDHD mutations, the SDHD c.129G>A (p.W43X) variation displayed an earlier age at first diagnosis with a highly variable phenotype ranging from one benign, non-secreting paraganglioma to bilateral pheochromocytomas and recurrent parganagliomas along the parasympathetic chain from head to abdomen. This report contributes to the evolving understanding of the phenotypic presentations of various genetic mutations. We propose that expert guidelines that suggest screening family members with the SDHD c.129G>A (p.W43X) variation at the age of 8 for early detection of pheochromocytomas and paragangliomas is beneficial.