Germline Mutations Landscape in a Cohort of the State of Minas Gerais, Brazil, in Patients Who Underwent Genetic Counseling for Gynecological and Breast Cancer.

OBJECTIVE: The present study evaluated the profile of germline mutations present in patients who underwent genetic counseling for risk assessment for breast cancer (BC), ovarian cancer (OC), and endometrial cancer (EC) with a possible hereditary pattern. METHODS: Medical records of 382 patients who underwent genetic counseling after signing an informed consent form were analyzed. A total of 55.76% of patients (213/382) were symptomatic (personal history of cancer), and 44.24% (169/382) were asymptomatic (absence of the disease). The variables analyzed were age, sex, place of birth, personal or family history of BC, OC, EC, as well as other types of cancer associated with hereditary syndromes. The Human Genome Variation Society (HGVS) nomenclature guidelines were used to name the variants, and their biological significance was determined by comparing 11 databases. RESULTS: We identified 53 distinct mutations: 29 pathogenic variants, 13 variants of undetermined significance (VUS), and 11 benign. The most frequent mutations were BRCA1 c.470_471delCT, BRCA1 c.4675 + 1G > T, and BRCA2 c.2T> G. Furthermore, 21 variants appear to have been described for the first time in Brazil. In addition to BRCA1/2 mutations, variants in other genes related to hereditary syndromes that predispose to gynecological cancers were found. CONCLUSION: This study allowed a deeper understanding of the main mutations identified in families in the state of Minas Gerais and demonstrates the need to assess the family history of non-gynecological cancer for risk assessment of BC, OC, and EC. Moreover, it is an effort that contributes to population studies to evaluate the cancer risk mutation profile in Brazil.

OBJETIVO: O presente estudo avaliou o perfil de mutações germinativas presentes em pacientes submetidas a aconselhamento genético para avaliação de risco para câncer de mama (CM), câncer de ovário (OC) e câncer de endométrio (CE) com possível padrão hereditário. MéTODOS: Foram analisados os prontuários de 382 pacientes que realizaram aconselhamento genético após consentimento informado. Um total de 55,76% dos pacientes (213/382) eram sintomáticos (história pessoal de câncer), e 44,24% (169/382) eram assintomáticos (ausência da doença). As variáveis analisadas foram idade, sexo, naturalidade, história pessoal ou familiar de CM, OC, CE bem como outros tipos de câncer associados a síndromes hereditárias. As diretrizes de nomenclatura da Human Genome Variation Society (HGVS) foram usadas para nomear as variantes e seu significado biológico foi determinado pela comparação de 11 bancos de dados. RESULTADOS: Identificamos 53 mutações distintas: 29 variantes patogênicas, 13 variantes de significado indeterminado e 11 benignas. As mutações mais frequentes foram BRCA1 c.470_471delCT, BRCA1 c.4675 + 1G > T e BRCA2 c.2T > G. Além disso, 21 variantes parecem ter sido descritas pela primeira vez no Brasil. Além das mutações BRCA1/2, foram encontradas variantes em outros genes relacionados a síndromes hereditárias que predispõem a cânceres ginecológicos. CONCLUSãO: Este estudo permitiu conhecer melhor as principais mutações identificadas nas famílias do estado de Minas Gerais e demonstra a necessidade de avaliar a história familiar de câncer não ginecológico para avaliação do risco de CM, OC e CE. Além disso, é um esforço que contribui com estudos populacionais para avaliar o perfil de mutações de risco para câncer no Brasil.

Germline Mutations Landscape in a Cohort of the State of Minas Gerais, Brazil, in Patients Who Underwent Genetic Counseling for Gynecological and Breast Cancer / Cenário de mutações germinativas em uma coorte do estado de Minas Gerais, Brasil, em pacientes submetidas ao aconselhamento genético para câncer ginecológico e de mama

Abstract Objective The present study evaluated the profile of germline mutations present in patients who underwent genetic counseling for risk assessment for breast cancer (BC), ovarian cancer (OC), and endometrial cancer (EC) with a possible hereditary pattern. Methods Medical records of 382 patients who underwent genetic counseling after signing an informed consent form were analyzed. A total of 55.76% of patients (213/382) were symptomatic (personal history of cancer), and 44.24% (169/382) were asymptomatic (absence of the disease). The variables analyzed were age, sex, place of birth, personal or family history of BC, OC, EC, as well as other types of cancer associated with hereditary syndromes. The Human Genome Variation Society (HGVS) nomenclature guidelines were used to name the variants, and their biological significance was determined by comparing 11 databases. Results We identified 53 distinct mutations: 29 pathogenic variants, 13 variants of undetermined significance (VUS), and 11 benign. The most frequent mutations were BRCA1 c.470_471delCT, BRCA1 c.4675 + 1G > T, and BRCA2 c.2T> G. Furthermore, 21 variants appear to have been described for the first time in Brazil. In addition to BRCA1/2 mutations, variants in other genes related to hereditary syndromes that predispose to gynecological cancers were found. Conclusion This study allowed a deeper understanding of the main mutations identified in families in the state of Minas Gerais and demonstrates the need to assess the family history of non-gynecological cancer for risk assessment of BC, OC, and EC. Moreover, it is an effort that contributes to population studies to evaluate the cancer risk mutation profile in Brazil.

Resumo Objetivo O presente estudo avaliou o perfil de mutações germinativas presentes em pacientes submetidas a aconselhamento genético para avaliação de risco para câncer de mama (CM), câncer de ovário (OC) e câncer de endométrio (CE) com possível padrão hereditário. Métodos Foram analisados os prontuários de 382 pacientes que realizaram aconselhamento genético após consentimento informado. Um total de 55,76% dos pacientes (213/382) eram sintomáticos (história pessoal de câncer), e 44,24% (169/382) eram assintomáticos (ausência da doença). As variáveis analisadas foram idade, sexo, naturalidade, história pessoal ou familiar de CM, OC, CE bem como outros tipos de câncer associados a síndromes hereditárias. As diretrizes de nomenclatura da Human Genome Variation Society (HGVS) foram usadas para nomear as variantes e seu significado biológico foi determinado pela comparação de 11 bancos de dados. Resultados Identificamos 53 mutações distintas: 29 variantes patogênicas, 13 variantes de significado indeterminado e 11 benignas. As mutações mais frequentes foram BRCA1 c.470_471delCT, BRCA1 c.4675 + 1G > T e BRCA2 c.2T > G. Além disso, 21 variantes parecem ter sido descritas pela primeira vez no Brasil. Além das mutações BRCA1/2, foram encontradas variantes em outros genes relacionados a síndromes hereditárias que predispõem a cânceres ginecológicos. Conclusão Este estudo permitiu conhecer melhor as principais mutações identificadas nas famílias do estado de Minas Gerais e demonstra a necessidade de avaliar a história familiar de câncer não ginecológico para avaliação do risco de CM, OC e CE. Além disso, é um esforço que contribui com estudos populacionais para avaliar o perfil de mutações de risco para câncer no Brasil.

The germline mutational landscape of BRCA1 and BRCA2 in Brazil.

The detection of germline mutations in BRCA1 and BRCA2 is essential to the formulation of clinical management strategies, and in Brazil, there is limited access to these services, mainly due to the costs/availability of genetic testing. Aiming at the identification of recurrent mutations that could be included in a low-cost mutation panel, used as a first screening approach, we compiled the testing reports of 649 probands with pathogenic/likely pathogenic variants referred to 28 public and private health care centers distributed across 11 Brazilian States. Overall, 126 and 103 distinct mutations were identified in BRCA1 and BRCA2, respectively. Twenty-six novel variants were reported from both genes, and BRCA2 showed higher mutational heterogeneity. Some recurrent mutations were reported exclusively in certain geographic regions, suggesting a founder effect. Our findings confirm that there is significant molecular heterogeneity in these genes among Brazilian carriers, while also suggesting that this heterogeneity precludes the use of screening protocols that include recurrent mutation testing only. This is the first study to show that profiles of recurrent mutations may be unique to different Brazilian regions. These data should be explored in larger regional cohorts to determine if screening with a panel of recurrent mutations would be effective.

Use of a multiplex ligation-dependent probe amplification method for the detection of deletions/duplications in the GBA1 gene in Gaucher disease patients.

Gaucher disease (GD) is caused by the deficient activity of ß-glucocerebrosidase due to pathogenic mutations in the GBA1. This gene has a pseudogene (GBAP) with 96% of sequence homology. Recombination (Rec) events in the GBA1 seem to be facilitated by an increased degree of homology and proximity to the GBAP. The objectives of this study were to validate the P338-X1 GBA kit (MRC-Holland) for Multiplex Ligation-dependent Probe Amplification (MLPA) and to detect larger deletions/duplications present in GBA1 in GD patients from Brazil. Thirty-three unrelated Brazilian GD patients, previously genotyped by the Sanger method (both pathogenic alleles identified=29 patients, only one allele identified=3 patients, no pathogenic alleles identified=1 patient), were evaluated by the MLPA assay. MLPA was compatible with the previous results obtained by Sanger sequencing and identified an additional allele (a heterozygous deletion in intron 7 in one patient with only one mutation identified by Sanger). Our data suggest that, although larger deletions/duplications do not appear to be frequent in GD, the P338-X1 GBA kit for MLPA appears to be a good method for GBA1 analysis. Additional investigations should be performed in order to characterize the remaining four uncharacterized alleles of our sample.