ESPE Abstracts

Introduction: Primary hyperparathyroidism (PHPT), often caused by a single adenoma (80%–85%) or hyperplasia or adenomas involving multiple glands, is the major cause of hypercalcemia. PHPT is common and occurs in individuals of all ages, but its prevalence is lower in young adults. Parathyroid tumors and PHPT can be caused by germline (hereditary PHPT) or somatic mutations of tumor suppressor genes (e.g., multiple endocrine neoplasia type 1 and CDC73) and proto-oncogenes. Approximately 5%–15% of PHPT cases occur in a familial setting, either in an isolated form (familial isolated hyperparathyroidism) or associated with other syndromal features (MEN1-2A, familial hypocalciuric hypercalcemic). In 15-20% of sporadic parathyroid carcinomas a mutation in the CDC73 gene (HRTP2) is identified, which is why some authors, consider it a tumor suppressor gene.

Objective: To present a patient with a parathyroid adenoma carrying a deletion of the CDC73 gene in heterozygous state

Methods: We investigated the pathogenic mutations in the CDC73 gene and analyzed their relationship with the phenotype in the patient with PHPT and parathyroid adenoma using Multiplex-ligation dependent probe amplification (MLPA).

Results: A17-year-old female presented with pathological fracture of the middle third of the humerus with polyuria, polydipsia, radiographs with generalized osteopenia and osteolytic lesions and nephrocalcinosis.

Laboratories with calcium of 17 mg/dl and ionic calcium of 4.24 mmol/l. PTH 1834pmol/l. Phosphorus 3.6 mg/dl, alkaline phosphatase of 2037, bone densitometry -4 SD, scintigraphy with sestamibi showed oval mass in the left lower lobe probable left atypical parathyroid adenoma. Months later she became psychosis, 5 years later the tumor relapsed in the neck, showed cervical nodule reported as metastasis of parathyroid adenoma; with no evidence of parathyroid injury. With calcium 13mg/dl, PTH> 2000pmol/l. Genetic study reported a heterozygous deletion of the CDC73 gene.Genetic study reported a Heterozygous Deletion of the CDC73 gene, no family history of hyperthyroidism.

Conclusion: PHPT is the main cause of hypercalcemia. Although the most common disease is sporadic PHPT, due to a single adenoma, there are heritable forms in 10% of cases.Patients with parathyroid carcinoma should undergo a careful review of their family history and should be offered a genetic study of the CDC73 Gene.