[Clinical and molecular genetic analyses for a sporadic parathyroid carcinoma].

Objective: To analyze the clinical and molecular genetic characteristics of one patient with sporadic parathyroid carcinoma (s-PC).

Methods: The clinical profile, laboratory data and paraffin-embedded tissue sample of a s-PC patient were collected at our hospital. Genomic DNA was extracted from the leukocytes of peripheral blood and paraffin-embedded tissue of this patient. All 17 exons of HRPT2 gene including the flanking regions of introns were amplified by PCR. The mutations of HRPT2 gene were analyzed by directly sequencing the amplified DNA fragments. Parafibromin encoded by HRPT2 gene was analyzed by immunohistochemistry.

Results: The patient was diagnosed as s-PC by the clinical presentations, laboratory examinations and typical pathologic characteristics. HRPT2 germline mutation was identified as a base mutation at codon 222 (CGA > TGA) and caused a nonsense mutation at the codon (R222X) resulting in a truncated protein. Parafibromin was completely lost while comparing the normal parathyroid tissues by immunohistochemistry.

Conclusion: The altered expression of parafibromin caused by HRPT2 gene mutation is one of the molecular mechanisms for explaining the clinical manifestations of this patient.