Impacto da Existência de Múltiplas Isoformas da Proteína RAD51D na Avaliação da Conservação Evolutiva dos Resíduos de Aminoácidos e, consequentemente, na Classificação de suas Variantes Genéticas quanto à Patogenicidade

Abstract

The RAD51D gene is involved in the repair pathways of double-strand breaks in DNA during replication and is part of the BRCA1 and BRCA2 gene pathways. Pathogenic genetic variants in RAD51D have been associated with breast and ovarian cancers and have high penetrance. Classification of genetic variants according to pathogenicity is essential, as it allows guiding clinical conduct. Genetic variants are classified as benign (B), probably benign (PB), variants of uncertain significance (VUS), probably pathogenic (PP), or pathogenic (P). The main criteria for classifying a genetic variant are: 1. involvement of the gene with the phenotype; 2. allele frequency of the variant in the general population and patient samples; 3. evolutionary conservation of the residue (amino acid) affected by the variant; 4. predicted functional impact on RNA and protein levels; 5. Variant segregation in families and functional studies evaluating the impacts of the variant. The existence of isoforms makes it difficult to assess the evolutionary conservation of residues, since multiple alignment programs (e.g., BLAST and CLUSTAL Omega) do not separate isoforms before performing the alignment. RAD51D has at least 8 protein isoforms and the presence of these isoforms, or which one is the canonical isoform, varies according to the species/class. The objective of the present study is to evaluate the evolutionary conservation of each residue of the human canonical isoform of the RAD51D protein and other clinically or evolutionarily relevant isoforms.