Williams-Beuren Syndrome With Primary Hyperparathyroidism: A Rare Diagnosis In A Rare Genetic Syndrome

ABSTRACT Objective: This case report is the first to describe functional parathyroid disease in Williams-Beuren Syndrome (WBS). We report a patient with hypercalcemia in infancy and later in adulthood whose unusual complex of elfin facies and multiple medical comorbidities, including hypercalcemia, ultimately led to a diagnosis of WBS by fluorescent in situ hybridization. While hypercalcemia is a common finding in patients with WBS, parathyroid hormone levels are typically suppressed. Methods: This study consists of a case report and literature review conducted in a high-volume university endocrine surgery center. We describe a 58-year-old patient with elfin facies, recurrent hyperparathyroidism, friendly personality, cognitive impairment, recurrent cystitis, hypertension, and stroke who was treated surgically for primary hyperparathyroidism with durable cure of his hypercalcemia. Outcomes are measured with long-term biochemical confirmation of cure after several re-operative surgical interventions. Results: After two parathyroid explorations failed to cure the patient's primary hyperparathyroidism, re-operative resection of an abnormal parathyroid gland resulted in intra-operative parathyroid hormone normalization (300 pg/mL to 57 pg/mL) and subsequent long-term normocalcemia (25 months). Conclusion: Though hypercalcemia is a known feature of WBS, it has not been reported in association with primary hyperparathyroidism. In the setting of WBS, hypercalcemia should be thoroughly evaluated to exclude this condition, which can be surgically cured. Abbreviations: IIH = idiopathic infantile hypercalcemia IV = intravenous PHP = primary hyperparathyroidism PTH = parathyroid hormone TRPC3 = transient receptor potential C3 WBS = Williams-Beuren syndrome