Published in:
01-06-2012 | Original Article
A novel germline SDHB mutation in a gastrointestinal stromal tumor patient without bona fide features of the Carney–Stratakis dyad
Authors:
Ricardo Celestino, Jorge Lima, Alexandra Faustino, Valdemar Máximo, António Gouveia, João Vinagre, Paula Soares, José Manuel Lopes
Published in:
Familial Cancer
|
Issue 2/2012
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Abstract
Gastrointestinal stromal tumors (GISTs) are the most common mesenchyme neoplasms of the gastrointestinal tract. Gain-of-function somatic mutations of the KIT or PDGFRA genes represent the most prevalent molecular alterations in GISTs. In Carney–Stratakis dyad, patients portray germline mutations of the succinate dehydrogenase subunits B (SDHB), C (SDHC) and D (SDHD) and develop multifocal GISTs and multicentric paragangliomas (PGLs). We herein report a novel germline SDHB mutation (c.T282A—Ile44Asn) occurring in a 26 years-old patient diagnosed with a spindle cell intermediate risk GIST that did not present KIT/PDGFRA/BRAF gene mutations. Further analyses revealed loss of the wild-type SDHB allele and complete loss of SDHB expression in the tumor tissue. After genetic screening of other family members, we detected in the patient′s mother a SDHB mutation without any clinical/laboratorial evidence of GIST or PGL. Altogether, our findings (germline SDHB mutation with absence of PGL in the index case and of GIST and/or PGL in his mother) raise the possibility that this familiar setting corresponds to an incomplete phenotype of the Carney–Stratakis dyad.