ABSTRACT
Despite significant advances in the management of coronary artery disease (CAD) and reductions in annual mortality rates in recent decades, this disease remains the leading cause of death worldwide. Consequently, there is an ongoing need for efforts to address this situation. Current clinical algorithms to identify at-risk patients are particularly inaccurate in moderate-risk individuals. For this reason, the need for ancillary tests has been suggested, including predictive genetic screening. As genetic studies rapidly expand and genomic data becomes more accessible, numerous genetic risk scores have been proposed to identify and evaluate an individual's susceptibility to developing diseases, including CAD. The field of genetics has indeed made substantial contributions to risk prediction, particularly in cases where children have parents with premature CAD, resulting in an increased risk of up to 75%. The polygenic risk scores (PRSs) have emerged as a potentially valuable tool for understanding and stratifying an individual's genetic risk. The PRS is calculated as a weighted sum of single-nucleotide variants present throughout the human genome, identifiable through genome-wide association studies, and associated with various cardiometabolic diseases. The use of PRSs holds promise, as it enables the development of personalized strategies for preventing or diagnosing specific pathologies early. Furthermore, it can complement existing clinical scores, increasing the accuracy of individual risk prediction. Consequently, the application of PRSs has the potential to impact the costs and adverse outcomes associated with CAD positively. This narrative review provides an overview of the role of PRSs in the context of CAD.
Apesar dos avanços significativos no tratamento da doença arterial coronariana (DAC) e das reduções nas taxas de mortalidade anuais nas últimas décadas, a DAC continua sendo a principal causa de morte no mundo. Consequentemente, há uma necessidade contínua de esforços para abordar essa situação. Os algoritmos clínicos atuais para identificar pacientes em risco são particularmente imprecisos para indivíduos de risco moderado. Por esse motivo, foi sugerido que são necessários testes auxiliares, incluindo triagem genética preditiva. À medida que os estudos genéticos se expandem rapidamente e os dados genômicos se tornam mais acessíveis, diversos escores de risco genético têm sido propostos para identificar e avaliar a suscetibilidade de um indivíduo ao desenvolvimento de doenças, incluindo a DAC. De fato, o campo da genética tem contribuído substancialmente para a previsão de risco, particularmente nos casos em que as crianças têm genitores com DAC prematura, resultando em um risco aumentado de até 75%. Os escores de risco poligênico (PRSs, do inglês polygenic risk scores) surgiram como uma ferramenta potencialmente valiosa para compreender e estratificar o risco genético de um indivíduo. O PRS é calculado como uma soma ponderada de variantes de nucleotídeo único presentes em todo o genoma humano, identificáveis por meio de estudos de associação genômica ampla, e associadas a várias doenças cardiometabólicas. O uso dos PRSs é promissor, pois permite o desenvolvimento de estratégias personalizadas para prevenir ou diagnosticar patologias específicas de forma precoce. Ademais, seu uso é capaz de complementar os escores clínicos existentes, aumentando a precisão da previsão de risco individual. Consequentemente, a aplicação dos PRSs tem o potencial de impactar positivamente os custos e os desfechos adversos associados à DAC. A presente revisão narrativa oferece uma visão ampla do papel dos PRSs no contexto da DAC.
Subject(s)
Coronary Artery Disease , Genetic Predisposition to Disease , Genome-Wide Association Study , Multifactorial Inheritance , Humans , Coronary Artery Disease/genetics , Risk Assessment/methods , Genetic Predisposition to Disease/genetics , Multifactorial Inheritance/genetics , Risk Factors , Genetic Testing/methods , Polymorphism, Single Nucleotide/genetics , Genetic Risk ScoreABSTRACT
During the last decades, genomic medicine has made it possible to bring the knowledge of molecular genetics to the field of medical consultation. There are several studies that contribute to the diagnosis, the definition of prognoses, as well as the possibility of providing genetic counseling based on accurate scientific data. Advances in genomic sequencing have promoted the reclassification of entities according to an etiological criterion. Such is the case of epileptic encephalopathies, ataxias, dystonias, among many other neurological conditions. Its implementation requires strategies aimed at achieving the best diagnostic yield. This requires a greater understanding of the molecular bases of each of these practices, as well as their scope. They allow reducing the time until a certain diagnosis is made and the possibility, in some cases, of improving the quality of life of those affected with the use of tailored treatments. The objective of this article was to describe current laboratory studies, their scope and emphasize the algorithms for the study of genetic diseases in general, focusing the attention on those specific to neuropediatrics, in order to promote good practices, avoiding confusion, errors, and unnecessary expenditures of money and shortening the so-called "diagnostic odyssey".
Durante las últimas décadas la medicina genómica ha llevado al ámbito de la consulta médica los conocimientos de la genética molecular. Existe un número de estudios que contribuyen en el diagnóstico, la definición de pronósticos y posibilitan un asesoramiento genético basado en datos científicos certeros. En algunas enfermedades, los avances en la secuenciación genómica, ha promovido la reclasificación de entidades según un criterio etiológico, como las encefalopatías epilépticas, las ataxias, las distonías, entre muchas condiciones médicas. Su implementación requiere, por parte de los médicos, de estrategias tendientes a alcanzar el mejor rédito diagnóstico. Es necesario para ello, una mayor comprensión de las bases moleculares de estas prácticas, así como sus alcances. Permiten reducir los tiempos hasta la concreción de un diagnóstico de certeza y la posibilidad, en algunos casos, de mejorar la calidad de vida de los afectados con la utilización de tratamientos a la medida. El objetivo de este artículo fue describir las técnicas de laboratorio actuales, sus alcances y enfatizar los algoritmos de estudio de las enfermedades genéticas, haciendo hincapié en aquellas propias de la neuropediatría, a fin de propiciar las buenas prácticas, evitando confusiones, errores, erogaciones innecesarias de dinero y acortando la llamada "odisea diagnóstica".
Subject(s)
Genetic Testing , Nervous System Diseases , Humans , Genetic Counseling , Genetic Testing/methods , Genetic Testing/standards , Nervous System Diseases/genetics , Nervous System Diseases/diagnosis , Practice Guidelines as TopicABSTRACT
This paper examines how participants in genetic counseling sessions interactionally manage situations where the results of tests to investigate the causes of identified fetal malformations are inconclusive or missing. The dataset consists of 54 audio-recorded interactions at a unit specialized in moderate- and high-risk pregnancies at a Brazilian public hospital. Conversation analysis was used to examine the data, revealing that the participants deployed interactional actions that exhibited highly negative valence toward diagnostic inconclusiveness, demonstrating that when there is a motivation for a medical examination, insofar as its results will serve as a basis for subsequent decision-making (in this case about future pregnancies), there is a preference for bad diagnostic news over absent or inconclusive diagnostic news. These findings are consistent with prior interactional studies.
Este artigo examina como os participantes em sessões de aconselhamento genético gerenciam interacionalmente resultados de testes genéticos inconclusivos ou ausentes testes para investigar as causas das malformações fetais identificadas. O conjunto de dados consiste em 54 interações gravadas em áudio em uma unidade de gestação de médio e alto risco de um hospital público brasileiro. A abordagem da Análise da Conversa utilizada para examinar os dados revela que os participantes desenvolvem ações interacionais que exibem uma orientação de valência altamente negativa em relação à inconclusividade diagnóstica, demonstrando que quando há motivação para um exame médico, ou seja, usando o resultado do teste diagnóstico como base para tomada de decisão, tal como acontece com futuras gestações, haja uma preferência por más notícias diagnósticas em detrimento de notícias diagnósticas ausentes ou inconclusivas. Tais resultados são consistentes com estudos interacionais anteriores.
Este artículo examina cómo los participantes en las sesiones de asesoramiento genético gestionan de forma interactiva los resultados de pruebas genéticas no concluyentes o faltantes, pruebas para investigar las causas de las malformaciones fetales identificadas. El conjunto de datos consta de 54 interacciones grabadas en audio en una unidad de embarazo de riesgo medio y alto de un hospital público brasileño. El enfoque de Análisis de Conversación utilizado para examinar los datos revela que los participantes desarrollan acciones interaccionales que exhiben una orientación de valencia altamente negativa hacia la falta de conclusión del diagnóstico, lo que demuestra que cuando hay motivación para un examen médico, es decir, utilizar el diagnóstico del resultado de la prueba como base para la toma de decisiones, como ocurre con futuros embarazos, se prefieran las malas noticias diagnósticas a las noticias diagnósticas ausentes o no concluyentes. Estos resultados son consistentes con estudios interaccionales previos.
Subject(s)
Congenital Abnormalities , Genetic Testing , Decision Making , Observational Study , Genetic Counseling , Medical Examination , Diagnostic Techniques and Procedures , Counseling , MethodsABSTRACT
BACKGROUND: In this article, we delineate a loosely selected cohort comprising patients with a history of early-onset breast cancer and/or a familial occurrence of cancer. The aim of this study was to gain insights into the presence of breast cancer-related gene variants in a population from a micro-region in southern Brazil, specifically the Metropolitan Region of Curitiba. This area exhibits a highly genetically mixed population, mirroring the general characteristics of the Brazilian people. METHODS: Comprehensive next-generation sequencing (NGS) multigene panel testing was conducted on 12 patients from the region, utilizing three different library preparation methods. RESULTS: Two pathogenic variants and one candidate pathogenic variant were identified: BRCA2 c.8878C>T, p.Gln2960Ter; CHEK2 c.1100del, p.Thr367Metfs15, and BRCA2 c.3482dup, p.Asp1161Glufs3. CONCLUSION: BRCA2 c.3482dup, a novel candidate pathogenic variant, previously unpublished, is reported. The prevalence of pathogenic variants in this small cohort is similar to that described in the literature. All different library preparation methods were equally proficient in enabling the detection of these variants.
Subject(s)
BRCA2 Protein , Breast Neoplasms , Checkpoint Kinase 2 , High-Throughput Nucleotide Sequencing , Humans , BRCA2 Protein/genetics , Female , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Checkpoint Kinase 2/genetics , Brazil , Middle Aged , Adult , High-Throughput Nucleotide Sequencing/methods , Genetic Testing/methods , Genetic Testing/standards , Genetic Predisposition to DiseaseABSTRACT
Advances in DNA sequencing technologies, especially next-generation sequencing (NGS), which is the basis for whole-exome sequencing (WES) and whole-genome sequencing (WGS), have profoundly transformed immune-mediated rheumatic disease diagnosis. Recently, substantial cost reductions have facilitated access to these diagnostic tools, expanded the capacity of molecular diagnostics and enabled the pursuit of precision medicine in rheumatology. Understanding the fundamental principles of genetics and diversity in genetic variant classification is a crucial milestone in rheumatology. However, despite the growing availability of DNA sequencing platforms, a significant number of autoinflammatory diseases (AIDs), neuromuscular disorders, hereditary collagen diseases, and monogenic bone diseases remain unsolved, and variants of uncertain significance (VUS) pose a formidable challenge to addressing these unmet needs in the coming decades. This article aims to provide an overview of the clinical indications and interpretation of comprehensive genetic testing in the medical field, addressing the related complexities and implications.
Subject(s)
Genetic Testing , Rheumatic Diseases , Humans , Genetic Testing/methods , Rheumatic Diseases/genetics , Rheumatic Diseases/diagnosis , High-Throughput Nucleotide Sequencing , Rheumatology , Exome Sequencing , Neuromuscular Diseases/genetics , Neuromuscular Diseases/diagnosis , Hereditary Autoinflammatory Diseases/genetics , Hereditary Autoinflammatory Diseases/diagnosis , RheumatologistsABSTRACT
PURPOSE: To assess the impact of maternal age on the association between maternal basal FSH and aneuploidy. METHODS: A retrospective study including data from 1749 blastocysts diagnosed as euploid or aneuploid by PGT-A (preimplantation genetic testing for aneuploidy). Aneuploidy incidence was compared between embryos from mothers with high vs. low basal FSH levels (above and below the group median, respectively) in total, pre-AMA (advanced maternal age; < 35 years, 198 embryos) and AMA (≥ 35 years, 1551 embryos) patient groups, separately. To control for the interference of potentially confounding variables, the association between aneuploidy and high basal FSH levels was assessed by multivariate logistic analysis in overall, pre-AMA and AMA patient groups. RESULTS: Overall, aneuploidy rate was 9% higher (p = 0.02) in embryos from patients with high basal FSH (63.7%) compared to those with low basal FSH (58.4%). In the pre-AMA subgroup, aneuploidy incidence was 35% higher (p = 0.04) in embryos from patients with high basal FSH (53.5%) compared to those with low basal FSH (39.4%). Differently, aneuploidy occurrence did not vary between embryos from AMA patients with low (61.0%) and high (64.8%) basal FSH (p = 0.12). The multivariate analysis revealed that, in pre-AMA embryos, the association between aneuploidy occurrence and high basal FSH is independent of potential confounding variables (p = 0.04). CONCLUSION: Maternal basal FSH values are associated with embryo aneuploidy in pre-AMA but not in AMA patients. The present findings suggest that basal FSH is a useful parameter to assess aneuploidy risk in pre-AMA patients and reinforce the hypothesis that excessive FSH signalling can predispose to oocyte meiotic errors.
Subject(s)
Aneuploidy , Follicle Stimulating Hormone , Maternal Age , Humans , Female , Adult , Follicle Stimulating Hormone/blood , Pregnancy , Preimplantation Diagnosis , Retrospective Studies , Incidence , Blastocyst/metabolism , Fertilization in Vitro , Embryo Transfer , Genetic Testing , Pregnancy RateABSTRACT
Dear Editor, In relation to the letter expressing concerns about some important points of the article entitled "The usefulness of the genetic panel in the classification and refinement of diagnostic accuracy of Mexican patients with Marfan syndrome and other connective tissue disorders", we would like to comment on the following. Read more in the PDF.
Subject(s)
Connective Tissue Diseases , Marfan Syndrome , Humans , Marfan Syndrome/genetics , Marfan Syndrome/diagnosis , Mexico , Connective Tissue Diseases/genetics , Connective Tissue Diseases/diagnosis , Genetic Testing/methodsABSTRACT
OBJECTIVE: The current study delves into the accessibility of genetic evaluations for individuals with orofacial clefts (OC), comparing data between genetics and treatment centers across Brazil. METHODS: This cross-sectional retrospective study analyzed primary data from 1463 OC individuals registered in the Brazilian Database of Craniofacial Anomalies (BDCA) between 2008 and 2018 without age or sex selection. Diagnostic exam results stemming from research projects until 2023 were considered. RESULTS: Of the 1463 individuals with typical OC, 987 were non-syndromic, 462 were syndromic (SOC), 10 presented atypical forms, and three were not specified OC cases. The average age for accessing laboratory diagnosis was 8.5 years among SOC individuals. Notably, more SOC cases were registered in genetics centers than treatment and rehabilitation centers (37.1 % vs. 29 %, p = 0.0015). Those originating from genetics centers accessed diagnosis at an average age of 7.3 years, while those from treatment and rehabilitation centers experienced delays with an average age of 10.7 years (p = 0.0581). CONCLUSIONS: Irrespective of the center of origin, the data highlight delayed diagnosis and challenges in accessing genetic tests for the syndromic group. Given the widespread reliance on the public health system by most of the Brazilian population, disseminating this data can significantly contribute to shaping an informed perspective on healthcare access. These insights can improve public policies tailored to the unique needs of individuals with OC.
Subject(s)
Cleft Lip , Cleft Palate , Genetic Testing , Health Services Accessibility , Humans , Brazil , Cross-Sectional Studies , Retrospective Studies , Female , Male , Child , Cleft Lip/genetics , Cleft Palate/genetics , Health Services Accessibility/statistics & numerical data , Child, Preschool , Adolescent , InfantABSTRACT
BACKGROUND: Albinism is a heterogeneous condition in which patients present complete absence, reduction, or normal pigmentation in skin, hair and eyes in addition to ocular defects. One of the heterogeneous forms of albinism is observed in Hermansky-Pudlak syndrome (HPS) patients. HPS is characterized by albinism and hemorrhagic diathesis due to the absence of dense bodies in platelets. METHODS: In this report, we describe a case of a pair of Puerto Rican siblings with albinism that were clinically diagnosed with HPS during childhood. Since they did not harbor the founder changes in the HPS1 and HPS3 genes common in Puerto Ricans, as adults they wanted to know the type of albinism they had. We performed exome sequencing, validation by PCR, and cloning of PCR products followed by Sanger sequencing in the family members. RESULTS: We discovered no mutations that could explain an HPS diagnosis. Instead, we found the siblings were compound heterozygotes for 4 variants in the Tyrosinase gene: c.-301C>T, c.140G>A (rs61753180; p.G47D), c.575C>A (rs1042602; p.S192Y), and c.1205G>A (rs1126809; p.R402Q). Our results show that the correct diagnosis for the siblings is OCA1B. CONCLUSION: Our study shows the importance of molecular testing when diagnosing a rare genetic disorder, especially in populations were the disease prevalence is higher.
Subject(s)
Albinism, Oculocutaneous , Hermanski-Pudlak Syndrome , Monophenol Monooxygenase , Humans , Hermanski-Pudlak Syndrome/genetics , Hermanski-Pudlak Syndrome/diagnosis , Hermanski-Pudlak Syndrome/pathology , Albinism, Oculocutaneous/genetics , Albinism, Oculocutaneous/diagnosis , Monophenol Monooxygenase/genetics , Male , Female , Adult , Pedigree , Genetic Testing/methods , Mutation , HeterozygoteABSTRACT
In recent years, significant progress has been made in 5q Spinal Muscular Atrophy therapeutics, emphasizing the importance of early diagnosis and intervention for better clinical outcomes. Characterized by spinal cord motor neuron degeneration, 5q-SMA leads to muscle weakness, swallowing difficulties, respiratory insufficiency, and skeletal deformities. Recognizing the pre-symptomatic phases supported by screening and confirmatory genetic tests is crucial for early diagnosis. This work addresses key considerations in implementing 5q-SMA screening within the Brazilian National Newborn Screening Program and explores Brazil's unique challenges and opportunities, including genetic tests, time-to-patient referral to specialized centers, program follow-up, and treatment algorithms. We aim to guide healthcare professionals and policymakers, facilitating global discussions, including Latin American countries, and knowledge-sharing on this critical subject to improve the care for newborns identified with 5q SMA.
Subject(s)
Muscular Atrophy, Spinal , Neonatal Screening , Humans , Infant, Newborn , Neonatal Screening/methods , Muscular Atrophy, Spinal/diagnosis , Muscular Atrophy, Spinal/genetics , Muscular Atrophy, Spinal/therapy , Brazil , Genetic Testing/methods , Early Diagnosis , Patient Care/methods , Spinal Muscular Atrophies of Childhood/diagnosis , Spinal Muscular Atrophies of Childhood/genetics , Spinal Muscular Atrophies of Childhood/therapyABSTRACT
Despite the high prevalence of TP53 pathogenic variants (PV) carriers in the South and Southeast regions of Brazil, germline genetic testing for hereditary breast cancer (HBC) is not available in the Brazilian public health system, and the prevalence of Li-Fraumeni syndrome (LFS) is not well established in other regions of Brazil. We assessed the occurrence of TP53 p.R337H carriers among women treated for breast cancer (BC) between January 2021 and January 2022 at public hospitals of Brasilia, DF, Brazil. A total of 180 patients who met at least one of the NCCN criteria for HBC underwent germline testing; 44.4% performed out-of-pocket germline multigene panel testing, and 55.6% were tested for the p.R337H variant by allelic discrimination PCR. The median age at BC diagnosis was 43.5 years, 93% had invasive ductal carcinoma, 50% had estrogen receptor-positive/HER2 negative tumors, and 41% and 11% were diagnosed respectively at stage III and IV. Two patients (1.11%) harbored the p.R337H variant, and cascade family testing identified 20 additional carriers. The TP53 p.R337H detection rate was lower than that reported in other studies from south/southeast Brazil. Nonetheless, identifying TP53 PV carriers through genetic testing in the Brazilian public health system could guide cancer treatment and prevention.
Subject(s)
Breast Neoplasms , Genetic Predisposition to Disease , Germ-Line Mutation , Tumor Suppressor Protein p53 , Humans , Female , Breast Neoplasms/genetics , Breast Neoplasms/epidemiology , Brazil/epidemiology , Adult , Tumor Suppressor Protein p53/genetics , Middle Aged , Genetic Testing/methods , Public Health , Li-Fraumeni Syndrome/genetics , Li-Fraumeni Syndrome/epidemiology , AgedABSTRACT
PURPOSE: To define the spectrum of germline pathogenic variants (PVs) and copy number variant (CNV) in cancer susceptibility genes to the burden of breast and ovarian cancer (BC, OvC) in high-risk Brazilians in Minas Gerais with health insurance, southeast Brazil, undergoing multigene panel testing (MGPT). METHODS: Genotyping eligible individuals with health insurance in the Brazilian healthcare system for Hereditary Breast and Ovarian Cancer Syndrome to undergo molecular testing for 44 or 141-gene panels, a decision that was insurance driven. RESULTS: Overall, 701 individuals clinically defined as high BC/OvC risk, underwent MGPT from 1/2021 to 10/2022, with ~ 50% genotyped with a 44-gene panel and the rest with a 141-gene panel. Overall, 16.4% and 22.6% of genotyped individuals harbored PVs using 44-gene and the 141 gene panel, respectively. The most frequently mutated genes were: BRCA2 (3.7%); BRCA1 (3.6%) and monoallelic MUTYH (3.1%). CONCLUSION: The rate of PVs detected in high-risk individuals in this study was twice the 10% threshold used in Brazilian health guidelines. MGPT doubled the detection rate of PVs in cancer susceptibility genes in high-risk individuals compared with BRCA1/BRCA2 genotyping alone. The spectrum of PVs in Southern Brazil is diverse, with few recurring variants such as TP53 (0.6%), suggesting regional founder effects. The use of MGPT in hereditary cancer in Minas Gerais significantly increased the detection rate of P/LPVs compared to existing guidelines and should be considered as the primary genotyping modality in assessing hereditary cancer risk in Brazil.
Subject(s)
Genetic Predisposition to Disease , Genetic Testing , Germ-Line Mutation , Humans , Female , Brazil/epidemiology , Middle Aged , Adult , Genetic Testing/methods , Hereditary Breast and Ovarian Cancer Syndrome/genetics , Hereditary Breast and Ovarian Cancer Syndrome/epidemiology , DNA Copy Number Variations , Ovarian Neoplasms/genetics , Ovarian Neoplasms/epidemiology , Ovarian Neoplasms/pathology , Aged , BRCA2 Protein/genetics , Breast Neoplasms/genetics , Breast Neoplasms/epidemiology , Breast Neoplasms/pathology , Genotype , BRCA1 Protein/genetics , DNA GlycosylasesABSTRACT
Dear Editor, We have read the article "The usefulness of the genetic panel in the classification and refinement of diagnostic accuracy of Mexican patients with Marfan syndrome and other connective tissue disorders", recently published in your esteemed journal. We are a team dedicated to diagnosing, approaching, and managing patients with connective tissue disorders, particularly hypermobile spectrum disorders (HSD) and Ehlers-Danlos syndromes (EDS). We appreciate the research group's effort to address the complexity of connective tissue disorders using a multi-panel genetic approach and their analysis of genotype-phenotype associations in a cohort of Mexican patients. However, we would like to express our concern regarding two specific points that we consider crucial for the comprehensive understanding and management of these disorders. Read more in the PDF.
Subject(s)
Connective Tissue Diseases , Marfan Syndrome , Humans , Marfan Syndrome/genetics , Marfan Syndrome/diagnosis , Mexico , Connective Tissue Diseases/genetics , Connective Tissue Diseases/diagnosis , Genetic Testing/methods , Genetic Association Studies/methodsABSTRACT
PMS2, a Lynch Syndrome gene, presents challenges in genetic testing due to the existence of multiple pseudogenes. This study aims to describe a series of cases harboring a variant in the PMS2CL pseudogene that has been incorrectly assigned to PMS2 with different nomenclatures. We reviewed data from 647 Brazilian patients who underwent multigene genetic testing at a single center to identify those harboring the PMS2 V1:c.2186_2187delTC or V2:c.2182_2184delACTinsG variants, allegedly located at PMS2 exon 13. Gene-specific PCR and transcript sequencing was performed. Among the 647 individuals, 1.8% (12) carried the investigated variants, with variant allele frequencies ranging from 15 to 34%. By visually inspecting the alignments, we confirmed that both V1 and V2 represented the same variant and through gene-specific PCR and PMS2 transcript analysis, we demonstrated that V1/V2 is actually located in the PMS2CL pseudogene. Genomic databases (ExAC and gnomAD) report an incidence of 2.5 - 5.3% of this variant in the African population. Currently, V1 is classified as "uncertain significance" and V2 as "conflicting" in ClinVar, with several laboratories classifying them as "pathogenic". We identified a frequent African PMS2CL variant in the Brazilian population that is misclassified as a PMS2 variant. It is likely that V1/V2 have been erroneously assigned to PMS2 in several manuscripts and by clinical laboratories, underscoring a disparity-induced matter. Considering the limitations of short-read NGS differentiating between certain regions of PMS2 and PMS2CL, using complementary methodologies is imperative to provide an accurate diagnosis.
Subject(s)
Mismatch Repair Endonuclease PMS2 , Pseudogenes , Humans , Mismatch Repair Endonuclease PMS2/genetics , Brazil , Pseudogenes/genetics , Female , Male , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Middle Aged , Genetic Testing/methods , Adult , Gene Frequency , AgedABSTRACT
Exome and genome sequencing (ES/GS) are routinely used for the diagnosis of genetic diseases in developed countries. However, their implementation is limited in countries from Latin America. We aimed to describe the results of GS in patients with suspected rare genetic diseases in Colombia. We studied 501 patients from 22 healthcare sites from January to December 2022. GS was performed in the index cases using dried blood spots on filtercards. Ancestry analysis was performed under iAdmix. Multiomic testing was performed when needed (biomarker, enzymatic activity, RNA-seq). All tests were performed at an accredited genetic laboratory. Ethnicity prediction data confirmed that 401 patients (80%) were mainly of Amerindian origin. A genetic diagnosis was established for 142 patients with a 28.3% diagnostic yield. The highest diagnostic yield was achieved for pathologies with a metabolic component and syndromic disorders (p < 0.001). Young children had a median of 1 year of diagnostic odyssey, while the median time for adults was significantly longer (15 years). Patients with genetic syndromes have spent more than 75% of their life without a diagnosis, while for patients with neurologic and neuromuscular diseases, the time of the diagnostic odyssey tended to decrease with age. Previous testing, specifically karyotyping or chromosomal microarray were significantly associated with a longer time to reach a definitive diagnosis (p < 0.01). Furthermore, one out of five patients that had an ES before could be diagnosed by GS. The Colombian genome project is the first Latin American study reporting the experience of systematic use of diagnostic GS in rare diseases.
Subject(s)
Rare Diseases , Whole Genome Sequencing , Humans , Colombia , Rare Diseases/genetics , Rare Diseases/diagnosis , Adult , Male , Female , Child , Whole Genome Sequencing/standards , Adolescent , Child, Preschool , Genetic Testing/methods , Genetic Testing/standards , Middle Aged , InfantABSTRACT
BACKGROUND: In Colombia and worldwide, breast cancer (BC) is the most frequently diagnosed neoplasia and the leading cause of death from cancer among women. Studies predominantly involve hereditary and familial cases, demonstrating a gap in the literature regarding the identification of germline mutations in unselected patients from Latin-America. Identification of pathogenic/likely pathogenic (P/LP) variants is important for shaping national genetic analysis policies, genetic counseling, and early detection strategies. The present study included 400 women with unselected breast cancer (BC), in whom we analyzed ten genes, using Whole Exome Sequencing (WES), know to confer risk for BC, with the aim of determining the genomic profile of previously unreported P/LP variants in the affected population. Additionally, Multiplex Ligation-dependent Probe Amplification (MLPA) was performed to identify Large Genomic Rearrangements (LGRs) in the BRCA1/2 genes. To ascertain the functional impact of a recurrent intronic variant (ATM c.5496 + 2_5496 + 5delTAAG), a minigene assay was conducted. RESULTS: We ascertained the frequency of P/LP germline variants in BRCA2 (2.5%), ATM (1.25%), BRCA1 (0.75%), PALB2 (0.50%), CHEK2 (0.50%), BARD1 (0.25%), and RAD51D (0.25%) genes in the population of study. P/LP variants account for 6% of the total population analyzed. No LGRs were detected in our study. We identified 1.75% of recurrent variants in BRCA2 and ATM genes. One of them corresponds to the ATM c.5496 + 2_5496 + 5delTAAG. Functional validation of this variant demonstrated a splicing alteration probably modifying the Pincer domain and subsequent protein structure. CONCLUSION: This study described for the first time the genomic profile of ten risk genes in Colombian women with unselected BC. Our findings underscore the significance of population-based research, advocating the consideration of molecular testing in all women with cancer.
Subject(s)
BRCA2 Protein , Breast Neoplasms , Genetic Predisposition to Disease , Germ-Line Mutation , Humans , Female , Germ-Line Mutation/genetics , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Breast Neoplasms/epidemiology , Colombia/epidemiology , Middle Aged , Adult , BRCA2 Protein/genetics , BRCA1 Protein/genetics , Exome Sequencing , Aged , Genetic Testing/methods , Ataxia Telangiectasia Mutated Proteins/geneticsABSTRACT
Low-pass whole genome sequencing (LP-WGS) has been applied as alternative method to detect copy number variants (CNVs) in the clinical setting. Compared with chromosomal microarray analysis (CMA), the sequencing-based approach provides a similar resolution of CNV detection at a lower cost. In this study, we assessed the efficiency and reliability of LP-WGS as a more affordable alternative to CMA. A total of 1363 patients with unexplained neurodevelopmental delay/intellectual disability, autism spectrum disorders, and/or multiple congenital anomalies were enrolled. Those patients were referred from 15 nonprofit organizations and university centers located in different states in Brazil. The analysis of LP-WGS at 1x coverage (>50kb) revealed a positive testing result in 22% of the cases (304/1363), in which 219 and 85 correspond to pathogenic/likely pathogenic (P/LP) CNVs and variants of uncertain significance (VUS), respectively. The 16% (219/1363) diagnostic yield observed in our cohort is comparable to the 15%-20% reported for CMA in the literature. The use of commercial software, as demonstrated in this study, simplifies the implementation of the test in clinical settings. Particularly for countries like Brazil, where the cost of CMA presents a substantial barrier to most of the population, LP-WGS emerges as a cost-effective alternative for investigating copy number changes in cytogenetics.