Cancer risk-reducing surgery: Brazilian Society of Surgical Oncology Guideline Part 2 (Gastrointestinal and thyroid).

BACKGROUND: Risk-reducing operations are an important part of the management of hereditary predisposition to cancer. In selected cases, they can considerably reduce the morbidity and mortality associated with cancer in this population. OBJECTIVES: The Brazilian Society of Surgical Oncology (BSSO) developed this guideline to establish national benchmarks for cancer risk-reducing operations. METHODS: The guideline was prepared from May to December 2021 by a multidisciplinary team of experts to discuss the surgical management of cancer predisposition syndromes. Eleven questions were defined and assigned to expert groups that reviewed the literature and drafted preliminary recommendations. Following a review by the coordinators and a second review by all participants, the groups made final adjustments, classified the level of evidence, and voted on the recommendations. RESULTS: For all questions including risk-reducing colectomy, gastrectomy, and thyroidectomy, a major agreement was achieved by the participants, always using accessible alternatives. CONCLUSION: This and its accompanying article represent the first guideline in cancer risk reduction surgery developed by the BSSO and it should serve as an important reference for the management of families with cancer predisposition.

Aberrant transcript produced by a splice donor site deletion in the TECTA gene is associated with autosomal dominant deafness in a Brazilian family.

We ascertained a Brazilian family with nine individuals affected by autosomal dominant nonsyndromic sensorineural hearing loss. The bilateral hearing loss affected mainly mid-high frequencies, was apparently stable with an early onset. Microsatellites close to the DFNA8/DFNA12 locus, which harbors the TECTA gene, showed significant multipoint lod scores (3.2) close to marker D11S4107. Sequencing of the exons and exon-intron boundaries of the TECTA gene in one affected subject revealed the deletion c.5383+5delGTGA in the 5' end of intron 16, that includes the last two bases of the donor splice site consensus sequence. This mutation segregates with deafness within the family. To date, 33 different TECTA mutations associated with autossomal dominant hearing loss have been described. Among them is the mutation reported herein, first described by Hildebrand et al. (2011) in a UK family. The audioprofiles from the UK and Brazilian families were similar. In order to investigate the transcripts produced by the mutated allele, we performed cDNA analysis of a lymphoblastoid cell line from an affected heterozygote with the c.5383+5delGTGA and a noncarrier from the same family. The analysis allowed us to identify an aberrant transcript with skipping of exon 16, without affecting the reading frame. One of the dominant TECTA mutations already described, a synonymous substitution in exon 16 (c.5331G

Genotype-phenotype correlation in Brazillian Rett syndrome patients.

BACKGROUND: Rett syndrome (RS) is a severe neurodevelopmental X-linked dominant disorder caused by mutations in the MECP2 gene. PURPOSE: To search for point mutations on the MECP2 gene and to establish a correlation between the main point mutations found and the phenotype. METHOD: Clinical evaluation of 105 patients, following a standard protocol. Detection of point mutations on the MECP2 gene was performed on peripheral blood DNA by sequencing the coding region of the gene. RESULTS: Classical RS was seen in 68% of the patients. Pathogenic point mutations were found in 64.1% of all patients and in 70.42% of those with the classical phenotype. Four new sequence variations were found, and their nature suggests patogenicity. Genotype-phenotype correlations were performed. CONCLUSION: Detailed clinical descriptions and identification of the underlying genetic alterations of this Brazilian RS population add to our knowledge of genotype/phenotype correlations, guiding the implementation of mutation searching programs.

Genotype-phenotype correlation in Brazillian Rett syndrome patients / Correlação genótipo-fenótipo em pacientes brasileiras com síndrome de Rett

BACKGROUND: Rett syndrome (RS) is a severe neurodevelopmental X-linked dominant disorder caused by mutations in the MECP2 gene. PURPOSE: To search for point mutations on the MECP2 gene and to establish a correlation between the main point mutations found and the phenotype. METHOD: Clinical evaluation of 105 patients, following a standard protocol. Detection of point mutations on the MECP2 gene was performed on peripheral blood DNA by sequencing the coding region of the gene. RESULTS: Classical RS was seen in 68 percent of the patients. Pathogenic point mutations were found in 64.1 percent of all patients and in 70.42 percent of those with the classical phenotype. Four new sequence variations were found, and their nature suggests patogenicity. Genotype-phenotype correlations were performed. CONCLUSION: Detailed clinical descriptions and identification of the underlying genetic alterations of this Brazilian RS population add to our knowledge of genotype/phenotype correlations, guiding the implementation of mutation searching programs.

INTRODUÇÃO: A síndrome de Rett é uma grave doença do neurodesenvolvimento ligada ao X dominante, causada por mutações no gene MECP2. OBJETIVOS: Identificar mutações de ponto no gene MECP2 e estabelecer uma correlação entre as principais mutações encontradas e o fenótipo. MÉTODO: Avaliação clínica de 105 pacientes, seguindo um protocolo estabelecido. A identificação de mutações de ponto foi realizada em DNA de sangue periférico por sequenciamento da região codificante do gene amplificada por PCR. RESULTADOS: Em 68 por cento dos pacientes observou-se o quadro clássico da síndrome. Mutações de ponto patogênicas foram encontradas em 64,1 por cento dos pacientes e em 70,42 por cento das pacientes com o quadro clássico. Quatro novas variações de seqüência foram identificadas e sua natureza sugere patogenicidade. Correlações genótipo-fenótipo foram estabelecidas. CONCLUSÃO: Descrições clínicas detalhadas desta população brasileira de pacientes acrescenta conhecimento às correlações genótipo-fenótipo nesta grave condição, que podem auxiliar na implantação de programas de triagem de mutações.