Germline mutations in Patients with Apparently Sporadic Pheochromocytoma/Paraganglioma in Korea

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 37-82-Pheochromocytoma & Paraganglioma
Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-44
Jung Hee Kim*1, Hyung Jin Choi2, Eu Jeong Ku3, Sang Wan Kim4, Chan Soo Shin1, Moon-Woo Seong3, Kyu Eun Lee3 and Seong Yeon Kim1
1Seoul National University College of Medicine, Seoul, South Korea, 2Chungbuk National University College of Medicine, 3Seoul National University College of Medicine, 4Seoul Natinal Univ Boramae Hosp, Seoul, South Korea
Familial pheochromocytoma (PHEO) and paraganglioma (PGL) are often caused by germline mutations such as RET, VHL, SDHB and SDHD. Even in patients with apparently sporadic PHEO/PGL, germline mutations have been reported in 7.5~24%. The variation reflected the geographical and ethnic differences. Therefore, the need for genetic screening of germline mutations in apparently sporadic PHEO/PGL was prompted in our ethnic group. The aim of our study was to assess the frequency of germline mutations and develop the genetic testing strategy in patients with apparently sporadic PHEO/PGL in Korean population.

We recruited 52 patients who were diagnosed with nonsyndromic PHEO/PGL without a familiy history of the diseases in Seoul National University Hospital from 2009 to 2011. Genomic DNA was extracted from peripheral blood. All exons of succinate dehydrogenase complex B (SDHB), SDHD and VHL, and exons 10, 11, and 13 through 16 of RET genes were examined by direct sequencing and multiple ligation-dependent probe amplification. The clinical characteristics of each patient were assessed.

The study patients were composed of 26 men and 26 women, and mean age was 50.1 ± 13.5 years. Of them, 9 patients (17.2%) were diagnosed with PGL. One patient had PHEO and PGL simultaneously, who carried an SDHD mutation. The frequency of germline mutations was 13.5% (7/52): RET (n =2), VHL (n = 1), SDHB (n = 2), SDHD (n = 2). Five patients were diagnosed before the age of 30 years, of whom two patients were female and mutation carriers (SDHD and VHL). One patient with a mutation of SDHB had metastatic lesions in retrocaval lymph nodes. Other four patients with malignant pheochromocytoma showed no mutations in four genes. There were no significant differences between mutation and non-mutation carriers regarding age at onset, gender, location, tumor size and malignancy.

To our knowledge, there have been no studies performed in Asian ethnic groups to figure out the frequency of germline mutations in PHEO/PGL. The carriers of germline mutations in patients with apparently sporadic PHEO/PGL in our population were 13.5%, which was within the range of previous results. Some of clinical phenotypes were correlated with genotypes, but further studies are needed in a large number of patients.

Nothing to Disclose: JHK, HJC, EJK, SWK, CSS, MWS, KEL, SYK

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: Seoul National University Hospital Grant 04-2012-0340