Format

Send to

Choose Destination
J Bone Miner Res. 2017 Aug;32(8):1640-1643. doi: 10.1002/jbmr.3149. Epub 2017 Jun 2.

Recurrent Hyperparathyroidism Due to a Novel CDC73 Splice Mutation.

Author information

1
Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan, Ann Arbor, MI, USA.
2
Department of Surgery, Division of Endocrine Surgery, University of Michigan, Ann Arbor, MI, USA.
3
Department of Pathology, University of Michigan, Ann Arbor, MI, USA.

Abstract

The recognition of hereditary causes of primary hyperparathyroidism (pHPT) is important because clinical care and surveillance differ significantly between sporadic and hereditary pHPT. In addition, the increasing number of genetic tests poses a challenge to classify mutations as benign or pathogenic. Functional work-up of variants remains a mainstay to provide evidence for pathogenicity. We describe a 52-year-old male patient with recurrent pHPT since age 35 years. Despite several neck surgeries with complete parathyroidectomy, he experienced persistent pHPT, necessitating repeated surgery for a forearm autotransplant, which finally resulted in unmeasurable parathyroid hormone (PTH) levels. Genetic testing revealed a new CDC73 variant (c.238-8G>A [IVS2-8G>A]), initially classified as a variant of uncertain significance. Parathyroid tissue from the initial surgeries showed loss of heterozygosity. Using an RT-PCR approach, we show that the mutation leads to the use of a cryptic splice site in peripheral mononuclear cells. In addition, a minigene approach confirms the use of the cryptic splice site in a heterologous cell system. The novel c.238-8G>A CDC73 variant activates a cryptic splice site, and the functional data provided justify the classification as a likely pathogenic variant. Our results underscore the importance of functional work-up for variant classification in the absence of other available data, such as presence in disease-specific databases, other syndromic clinical findings, or family history. In addition, the presented case exemplifies the importance to consider a hereditary condition in young patients with pHPT, particularly those with multi-gland involvement.

KEYWORDS:

CDC73; HYPERPARATHYROIDISM; PARAFIBROMIN; SPLICE MUTATION

PMID:
28394026
DOI:
10.1002/jbmr.3149
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center