Mutational spectrum of the APC and MUTYH genes and genotype-phenotype correlations in Brazilian FAP, AFAP, and MAP patients

Autor(es)

Torrezan, Giovana Tardin ^[1] ; Carneiro da Silva, Felipe Cavalcanti ^[2] ; Monteiro Santos, Erika Maria ^[3] ; Victorino Krepischi, Ana Cristina ^[4] ; Waddington Achatz, Maria Isabel ^[5] ; Aguiar Junior, Samuel ^[6] ; Rossi, Benedito Mauro ^[7] ; Carraro, Dirce Maria ^[8]

Afiliação do(s) autor(es)

^[1] AC Camargo Hosp. Lab Genom & Mol Biol

^[2] AC Camargo Hosp. Lab Genom & Mol Biol

^[3] Natl Inst Sci & TechnolOncogenom INCITO. Sao Paulo

^[4] Natl Inst Sci & TechnolOncogenom INCITO. Sao Paulo

^[5] Natl Inst Sci & TechnolOncogenom INCITO. Sao Paulo

^[6] AC Camargo Hosp. Colorectal Tumors Dept

^[7] Barretos Canc Hosp. Pio Fdn 11

^[8] AC Camargo Hosp. Lab Genom & Mol Biol

• Tipo de documento: Artigo Científico
• Fonte: ORPHANET JOURNAL OF RARE DISEASES; v. 8, APR 5 2013.
• Citações Web of Science: 3

Resumo

Background: Patients with multiple colorectal adenomas are currently screened for germline mutations in two genes, APC and MUTYH. APC-mutated patients present classic or attenuated familial adenomatous polyposis (FAP/AFAP), while patients carrying biallelic MUTYH mutations exhibit MUTYH-associated polyposis (MAP). The spectrum of mutations as well as the genotype-phenotype correlations in polyposis syndromes present clinical impact and can be population specific, making important to obtain genetic and clinical data from different populations. Methods: DNA sequencing of the complete coding region of the APC and MUTYH genes was performed in 23 unrelated Brazilian polyposis patients. In addition, mutation-negative patients were screened for large genomic rearrangements by multiplex ligation-dependent probe amplification, array-comparative genomic hybridization, and duplex quantitative PCR. Biallelic MUTYH mutations were confirmed by allele-specific PCR. Clinical data of the index cases and their affected relatives were used to assess genotype-phenotype correlations. Results: Pathogenic mutations were identified in 20 of the 23 probands (87%): 14 in the APC gene and six in the MUTYH gene; six of them (30%) were described for the first time in this series. Genotype-phenotype correlations revealed divergent results compared with those described in other studies, particularly regarding the extent of polyposis and the occurrence of desmoid tumors in families with mutations before codon 1444 (6/8 families with desmoid). Conclusions: This first comprehensive investigation of the APC and MUTYH mutation spectrum in Brazilian polyposis patients showed a high detection rate and identified novel pathogenic mutations. Notably, a significant number of APC-positive families were not consistent with the predicted genotype-phenotype correlations from other populations. (AU)

• Processo FAPESP: 08/57887-9 - Instituto Nacional de Oncogenômica
• Beneficiário: Luiz Paulo Kowalski
• Modalidade de apoio: Auxílio à Pesquisa - Temático