Pathogenicity of DNA variants and double mutations in multiple endocrine neoplasia type 2 and von Hippel-Lindau syndrome.
BACKGROUND
Cancer genetics is fundamental for preventive medicine, in particular in pheochromocytoma-associated syndromes. Variants in two susceptibility genes, SDHC and RET, were found in a kindred with head and neck paraganglioma. This observation of coincident DNA variants, both reported as pathogenic, in two known susceptibility genes prompted the question of their pathogenic relevance.


OBJECTIVE
Our objective was to elucidate the pathogenic role of the detected variants and study the prevalence of such variants.


METHODS
Patients were registrants from the European-American Pheochromocytoma-Paraganglioma and German von Hippel-Lindau Disease Registries.


METHODS
Analysis of germline mutation screening results for all pheochromocytoma-paraganglioma susceptibility genes, including RET [multiple endocrine neoplasia type 2 (MEN 2)] and VHL [von Hippel-Lindau disease (VHL)]. Cases in which more than one DNA variant was found were clinically reevaluated, and cosegregation of the disease with the variant was analyzed within the registrants' families. A total of 1000 controls were screened for the presence of detected variants, and in silico analyses were performed.


RESULTS
Three variants were identified, RET p.Tyr791Phe and p.Ser649Leu and VHL p.Pro81Ser. The frequencies of RET p.Ser649Leu (0.07%) and p.Tyr791Phe (0.9%) compared with controls excluded the two variants' role in the etiology of MEN 2 and VHL. None of the carriers of the RET variants who underwent prophylactic thyroidectomy showed medullary thyroid carcinoma. Clinical reinvestigation of 18 variant carriers excluded MEN 2. VHL variant p.Pro81Ser, also previously described as a mutation, did not segregate with the VHL in one family. In silico analyses for these variants predicted unmodified protein function.


CONCLUSIONS
RET p.Tyr791Phe and p.Ser649Leu and VHL p.Pro81Ser are definitely not pathogenic mutations for VHL and MEN 2. Misinterpretation results in irreversible clinical consequences.
Erlic
Zoran
Z
Department of Nephrology, Section of Preventive Medicine, Albert-Ludwigs-University, Freiburg, D-79106 Freiburg, Germany.
Hoffmann
Michael M
MM
Sullivan
Maren
M
Franke
Gerlind
G
Peczkowska
Mariola
M
Harsch
Igor
I
Schott
Matthias
M
Gabbert
Helmut E
HE
Valimäki
Matti
M
Preuss
Simon F
SF
Hasse-Lazar
Kornelia
K
Waligorski
Dariusz
D
Robledo
Mercedes
M
Januszewicz
Andrzej
A
Eng
Charis
C
Neumann
Hartmut P H
HP
D000310:Adrenal Gland Neoplasms / Q000235:genetics; D004252:DNA Mutational Analysis; D005260:Female; D020022:Genetic Predisposition to Disease; D018095:Germ-Line Mutation / Q000502:physiology; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D018813:Multiple Endocrine Neoplasia Type 2a / Q000235:genetics*; D010235:Paraganglioma / Q000235:genetics; D010375:Pedigree; D010673:Pheochromocytoma / Q000235:genetics; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics*; D006623:von Hippel-Lindau Disease / Q000235:genetics*
D008565:Membrane Proteins; C108096:SDHC protein, human; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human