Genetic Link to Parathyroid Cancer Found

Researchers have identified the gene that when inactivated by mutation gives rise to hyperparathyroidism-jaw tumor syndrome (HPT-JT), a rare condition that leads to benign tumors of the parathyroid glands, jaw bones, and kidney along with the risk of parathyroid cancer. Their findings were reported in the November 18, 2002, online edition of Nature Genetics.

A multinational team of investigators headed by a group from the University of Utah School of Medicine (Salt Lake City, USA; www.uuhsc.utah.edu) identified 13 different heterozygous, germline, inactivating mutations in a single gene in 14 families with HPT–JT. In HPT-JT families, children have a 50% chance of inheriting the syndrome from an affected parent. Of those who inherit the syndrome, 85-90% develop the benign tumors, and 10-12% of these may eventually develop parathyroid cancer.

Development of HPT-JT was linked to the HRPT2 gene, which encodes parafibromin, a tumor-suppressing protein. Inactivation of HRPT2 gives rise to a parathyroid adenoma, a benign tumor in one of the four parathyroid glands. The adenoma manufactures excess parathyroid hormone, which results in calcium leaching from the bones into the blood.

Individuals at risk of HPT-JT can be screened for thyroid tumors by having their calcium and parathyroid hormone levels checked regularly. "We hope that early detection and surgical removal of benign tumors will reduce the incidence of parathyroid cancer in these families,” said senior author Dr. Maurine R. Hobbs, assistant research professor of internal medicine and human genetics at the University of Utah School of Medicine.



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