2023 ACMG Annual Clinical Genetics Meeting Digital Edition: Poster Gallery-Evaluation of Monoallelic <em>MUTYH </em>Variants in Brazilian Patients: Potential Selection Bias

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The study evaluated the presence of monoallelic MUTYH variants in Brazilian patients and assessed the potential selection bias in cancer risk assessment studies. MUTYH-associated polyposis (MAP) is a rare hereditary condition caused by mutations in the MUTYH gene. The association between monoallelic MUTYH mutations and the risk of colorectal cancer (CRC) or other cancers is still controversial. Previous studies have not found statistically significant associations, but the small number of carriers can affect the accuracy of risk data.<br /><br />To expand the understanding of MUTYH genotypes in the Brazilian population, the researchers conducted a descriptive study of patients at risk for hereditary cancer predisposition. Next Generation Sequencing (NGS) was used to analyze the MUTYH coding region in these patients. The clinical status of the patients was obtained from questionnaires filled before the genetic tests.<br /><br />Out of 2,654 patients, 63 (2.4%) had monoallelic MUTYH variants. Only 15 patients (23.8%) had isolated monoallelic variants in MUTYH without additional pathogenic or variant of unknown significance (VUS) variants. The mean age of these patients was 50 years, with 8 females and 7 males.<br /><br />The study concluded that only a small percentage of patients had completely isolated monoallelic MUTYH variants. It is important to consider the presence of other variants and avoid selection bias when assessing cancer risk in these patients. The study also identified a previously published exon 4-16 deletion in MUTYH.<br /><br />Further analysis is needed to better understand the impact of monoallelic MUTYH variants. In future studies, the researchers plan to describe the phenotype of this patient series in more detail.

Asset Subtitle

Presenting Author - Larissa SM. Bueno, MS; Co-Author - Daniele Paixão, PhD; Co-Author - THALITTA HA. LIMA, PhD; Co-Author - Juliana P. Carnavalli, MSc; Co-Author - Andrea Kiss, MD; Co-Author - Caroline M. Moreira, MSc; Co-Author - Miguel Mitne-Neto, PhD; Co-Author - Wagner Baratela, MD PhD;

Meta Tag

Cancer Syndromes

Delineation of Diseases

Genetic Testing

Genotype-Phenotype Correlations

NextGen Sequencing

Phenotypic delineation of disorders

Risk Assessment

Co-Author Daniele Paixão, PhD

Co-Author THALITTA HA. LIMA, PhD

Co-Author Juliana P. Carnavalli, MSc

Co-Author Andrea Kiss, MD

Co-Author Caroline M. Moreira, MSc

Co-Author Miguel Mitne-Neto, PhD

Co-Author Wagner Baratela, MD PhD

Presenting Author Larissa SM. Bueno, MS

Keywords

monoallelic MUTYH variants

Brazilian patients

cancer risk assessment

MUTYH-associated polyposis

MUTYH gene mutations

colorectal cancer risk

NGS analysis

hereditary cancer predisposition

exon 4-16 deletion

phenotype description