A Family with a Carotid Body Paraganglioma and Thyroid Neoplasias with a New SDHAF2 Germline Variant

At least 30% of all pheochromocytomas (PCCs)/paragangliomas (PGLs) arise in patients with a germline predisposition syndrome. Variants in succinate dehydrogenase subunits A, B, C, and D (SDHA, SDHB, SDHC, and SDHD) are the most common pathogenic germline alterations. Few pathogenic variants have been reported in succinate dehydrogenase assembly factor 2 (SDHAF2). Here, we describe a 30-year-old female patient who presented with a left-sided neck mass, which was later characterized as a carotid body PGL. Genetic testing revealed a likely pathogenic SDHAF2 variant (c.347G>A;p.W116X). Two sisters carried the same pathologic variant, and screening protocols were recommended. Whole-body MRI revealed thyroid nodules; this testing was followed by fine-needle aspiration, which confirmed papillary thyroid carcinoma in one sister and a follicular adenoma in the other. The two sisters then underwent hemithyroidectomy and total thyroidectomy, respectively. Because evidence for pathogenic variants in SDHAF2 causing predisposition to PCC/PGL is limited, we discuss the challenges in mutational variant interpretation and decision making regarding screening for associated tumors.