Genetic evaluation, familial screening and exercise

A prática de atividade física regular é benéfica para pessoas de todas as idades, gêneros e etnias.1 Se, por um lado, a prática do exercício moderado é considerada uma atividade saudável e favorável ao sistema cardiovascular, por outro, o exercício de alta intensidade por longo período de tempo pode aumentar o risco de morte súbita (MS).2 Mesmo considerando que um número imenso de pessoas faça exercício diariamente, a MS nesse cenário é considerada uma entidade rara. No entanto, a sua prevenção pode ser difícil e a mesma é de grande repercussão, principalmente quando incide em jovens praticantes de exercício recreativo ou em atletas. Do ponto de vista epidemiológico, a MS de origem cardíaca afeta entre 200 e 400 mil indivíduos nos Estados Unidos (EUA) anualmente.3 No âmbito dos esportes, estima-se que em torno de 200 atletas ao ano apresentem um evento fatal.4 Na Espanha, o registro nacional de MS em atletas descreveu 180 casos de 1995 até 2007, sugerindo uma incidência de 15 a 20 casos por ano.5 Em atletas, a avaliação pré-participação (APP) está indicada, podendo ser eficaz para a prevenção de MS cardíaca nesse contexto.6 Contudo, esse tipo de rastreamento apresenta grande variabilidade entre diferentes países e entidades que o realizam. No tocante à avaliação genética, essa se encontra relegada somente a casos específicos no contexto dos esportes. Nessa revisão descreveremos aspectos básicos da avaliação genética, assim como as indicações da análise molecular e sua correta interpretação clínica, tanto para esportistas recreativos ou amadores, quanto para os atletas de alto rendimento.Regular physical activity practice benefits individuals of all ages, sexes and ethnicities.1 If on one hand the practice of moderate exercise is considered a healthy activity that favors the cardiovascular system, on the other, high-intensity exercise for a long period can increase the risk for sudden death (SD).2 Even considering the huge number of individuals exercising daily, SD in that context is rare. However, the prevention of SD can be difficult and it has significant repercussion, mainly among young practitioners of leisure exercise or athletes. From the epidemiological viewpoint, cardiac SD affects 200,000 to 400,000 individuals in the United States of America (USA) annually.3 In the sports scenario, around 200 athletes per year are estimated to have a fatal event.4 In Spain, the national registry of SD in athletes reported 180 cases from 1995 to 2007, suggesting an incidence of 15 to 20 cases per year.5 For athletes, preparticipation evaluation (PPE) is indicated, and can be effective in preventing cardiac SD in that context.6 However, that type of screening has great variability between different countries and entities that perform it. In the sports context, genetic evaluation is performed only in specific cases. This review describes basic aspects of genetic evaluation, as well as the indications for molecular analysis and their correct clinical interpretation, for practitioners of recreational exercise, amateur sportsmen and high-performance athletes

Prognostic Implications of Pathogenic Truncating Variants in the TTN Gene

[Abstract] Introduction and objectives: TTN gene truncating variants (TTNtv) are a frequent cause of dilated cardiomyopathy (DCM). However, there are discrepant data on the associated prognosis. Our objectives were to describe the prevalence of TTNtv in our cohort and to compare the clinical course with that described in the literature. Methods: We included patients with DCM and genetic testing performed using next-generation sequencing. Through a systematic literature research, we collected information about carriers and affected relatives with TTNtv. We compared the cumulative percentage of affected carriers and the survival free of cardiovascular death. Results: One hundred and ten DCM patients were evaluated. A total of 13 TTNtv distributed in 14 probands were identified (12.7%). We found a 21.4% prevalence in familial cases. No significant differences in the relation between age and clinical disease expression were identified. Survival free of cardiovascular death curves constructed from data in the literature seems not to overestimate the risk in our population. Conclusions: The identification of TTNtv in patients with DCM is frequent and provides relevant information about the disease prognosis. The risk of cardiovascular death should not be underestimated. Age related penetrance need to be considered in the familial evaluation

High Performance of a Dominant/X-Linked Gene Panel in Patients with Neurodevelopmental Disorders

Neurodevelopmental disorders (NDDs) affect 2-5% of the population and approximately 50% of cases are due to genetic factors. Since de novo pathogenic variants account for the majority of cases, a gene panel including 460 dominant and X-linked genes was designed and applied to 398 patients affected by intellectual disability (ID)/global developmental delay (GDD) and/or autism (ASD). Pathogenic variants were identified in 83 different genes showing the high genetic heterogeneity of NDDs. A molecular diagnosis was established in 28.6% of patients after high-depth sequencing and stringent variant filtering. Compared to other available gene panel solutions for NDD molecular diagnosis, our panel has a higher diagnostic yield for both ID/GDD and ASD. As reported previously, a significantly higher diagnostic yield was observed: (i) in patients affected by ID/GDD compared to those affected only by ASD, and (ii) in females despite the higher proportion of males among our patients. No differences in diagnostic rates were found between patients affected by different levels of ID severity. Interestingly, patients harboring pathogenic variants presented different phenotypic features, suggesting that deep phenotypic profiling may help in predicting the presence of a pathogenic variant. Despite the high performance of our panel, whole exome-sequencing (WES) approaches may represent a more robust solution. For this reason, we propose the list of genes included in our customized gene panel and the variant filtering procedure presented here as a first-tier approach for the molecular diagnosis of NDDs in WES studies

Case report : Identification of a novel variant p.Gly215Arg in the CHN1 gene causing Moebius syndrome

Background: Moebius Syndrome (MBS) is a rare congenital neurological disorder characterized by paralysis of facial nerves, impairment of ocular abduction and other variable abnormalities. MBS has been attributed to both environmental and genetic factors as potential causes. Until now only two genes, PLXND1 and REV3L have been identified to cause MBS. Results: We present a 9-year-old male clinically diagnosed with MBS, presenting facial palsy, altered ocular mobility, microglossia, dental anomalies and congenital torticollis. Radiologically, he lacks both abducens nerves and shows altered symmetry of both facial and vestibulocochlear nerves. Whole-exome sequence identified a de novo missense variant c.643

Genética Clínica de la anemia de Fanconi

La anemia de Fanconi (AF) es un síndrome hereditario raro, de patrón recesivo mayoritariamente autosómico. Clínicamente se caracteriza por presentar malformaciones congénitas, fallo de médula ósea progresivo, endocrinopatías, predisposición a cáncer e hipersensibilidad celular a agente inductores de enlaces cruzados en el DNA (ICL). Esta enfermedad puede ser causada por mutacions bialélicas en cualquiera de los16 genes que hasta la fecha se han identificado, por lo cual existen 16 grupos de complementación. El grupo de complementación más frecuente a nivel mundial es el FA-A (63%) y su espectro mutacional es altamente heterogeneo. En la población Española la frecuencia de este grupo de complementaciòn es mayor (77%) debido a su alta prevalencia en la población gitana española. En este estudio se ha continuado con el análisis mutacional de los pacientes FA-A españoles usando la estrategia de análisis de las mutaciones más comunes y se ha iniciado en paralelo el análisis mutacional de poblaciones AF de algunos países Latino-americanos usando dicha estrategia. Adicionalmente, se ha estudiado el fenotipo celular de pacientes Fanconi-like y otros pacientes con fenotipo celular similar incluyendo un ensayo de fragilidad cromosómica negativo. Por otra parte, se ha realizado un estudio a largo plazo de la evolución hematológica de pacientes AF con mosaicismo somático hematológico. Finalmente, se ha analizado la tasa de eficiencia del diagnóstico genético preimplantacional (DGP) con tipificación del antígeno leucocitario humano (HLA) en parejas con hijos afectos de AF. Estos resultados confirman que la estrategia de cribado mutacional realizado en pacientes FA-A españoles es eficiente para identificar el 51% de las mutaciones en pacientes españoles y sólo el 17% de las mutaciones en la población Latino-americana estudiada hasta el momento. La implementación de la secuenciación masiva del exoma es muy eficiente para el subtipaje de pacientes AF, especialmente para los subtipos menos frecuentes, de esta manera se han subtipado dos pacientes españoles (FA104: FA-Q y FA287: FA-J). Con respecto al análisis de los pacientes Fanconi-like se observó que tienen una sensibilidad celular intermedia a agentes inductores de ICLs asociado a un fenotipo clínico similar a AF. Interesantemente, células derivadas de pacientes deficientes en FAN1 presentan una sensibilidad celular intermedia a agentes inductores de ICLs pero no presentan un fenotipo hematológico de AF, lo cual descarta a FAN1 como un gen candidato para AF. Por otra parte, se ha observado una mejoría hematológica en la mayoría de los pacientes AF con mosaicismo somático, pero con casos excepcionales que son relevantes para la predicción de resultados de futuros ensayos de terapia génica. Los resultados moleculares sugieren que la evolución clínica en estos pacientes no sólo depende del nivel celular donde ocurrió la reversión mutacional, sino también de la edad biológica y el potencial proliferativo de la célula revertida. Finalmente, se ha encontrado una baja tasa de éxito en parejas con hijos afectos con AF sometidas a DGP con tipificación HLA, muy probablemente debido a la edad materna avanzadaFanconi anemia (FA) is a rare genetic disorder, which is mainly inherited with autosomal recessive pattern. Clinically it is characterized by congenital and endocrine abnormalities, bone marrow failure, cancer predisposition and cellular hypersensitivity to DNA interstrand crosslinking agents (ICL). This disease is caused by biallelic mutations in any of 16 genes that have been identified so far, leading to 16 complementation groups. FA-A is the most common complementation group (63%) and its mutational spectrum is highly heterogeneous. In the Spanish population, the frequency of this complementation group is even higher (77%) due to its high prevalence in the Spanish gypsy population. In this study, we have continued the mutational analysis of Spanish FA-A patients by analyzing the most common mutations, and we also have started the mutational analysis of FA populations of some Latin-American countries by this strategy. In addition, we have studied the cellular phenotype of Fanconi-like patients and others patients with similar cellular phenotype including a negative chromosome fragility test. On the other hand, we have performed a long-term retrospective study of the hematological evolution of FA patients having hematologic somatic mosaicism. Finally, we have analyzed the rate of efficiency of preimplantation genetic diagnosis (PGD) with human leukocyte antigen (HLA) in couples with affected FA children. The results confirm that the mutational screening strategy adopted in Spanish FA-A patients is efficient to identify 51% of mutations in Spanish patients but only 17% of Latin-American populations studied so far. The implementation of whole exome sequencing is an efficient strategy for FA subtyping, especially for infrequent subtypes, as we have done confirming two Spanish patients (FA104: FA-Q and FA287:FA-J). It was observed that Fanconi-like patients share intermediate cell sensitivity to ICLs associated with clinical phenotype similar to FA. Interestingly, patient derived FAN1-deficient cells have intermediate cell sensitivity to ICLs but do not have a FA hematological phenotype, disregarding FAN1 as a candidate gene for FA. On the other hand, we have usually observed hematological improvement in patients with somatic mosaicism, but with exceptional cases that are relevant to predict the outcome of future gene therapy trials. The molecular results suggest that the clinical course in these patients depends not only on the cellular level where mutational reversion occurred but also on the biological age and proliferative potential of the reversed cell. Finally, we have found a very low success rate in couples with affected children with FA undergoing PGD with HLA typing, most probably due to the advanced maternal age

Savior siblings and Fanconi anemia : analysis of success rates from the family's perspective

Purpose:The current curative treatment of Fanconi anemia is hematopoietic stem cell transplantation; this treatment has a higher rate of successful outcome when donors are compatible siblings. Therefore some families opt to have a healthy and compatible baby after selecting an embryo using preimplantation genetic diagnosis with human leukocyte antigen (HLA) typing. This study aims to estimate the success rate of this procedure from the family's perspective.Methods:Genetic and embryology data were collected from genetic reports provided by the families.Results:A total of 524 oocytes (14.1 oocytes/cycle) and 299 embryos were generated (8.0 embryos/cycle) after 38 in vitro fertilization cycles. Sixteen embryos were transferred to the uterus because they were non-Fanconi anemia and HLA matched. One baby was born. A younger couple delivered a healthy and HLA-compatible baby after four cycles. Therefore, the success rate per cycle is less than 5% (two babies from 42 trials).Conclusion:While Fanconi anemia per se does not worsen the probability of success, a critical factor is advanced maternal age; a late diagnosis leads to few transferrable embryos and high rates of aneuploidy. Families should be informed in advance of the many trials that they will probably need to undergo even if a haploidentical younger relative is available as an oocyte donor

Abordaje de las cardiopatías familiares desde la Medicina genómica

Resumen: Las cardiopatías familiares son un grupo de enfermedades con alta heterogeneidad clínica y genética. Debido a que pueden heredarse y a su asociación con la muerte súbita, se recomienda efectuar un estudio clínico y genético del individuo afectado y su familia a través de una unidad especializada. Con la implementación de la secuenciación masiva se ha facilitado el acceso a los estudios genéticos en la práctica clínica de forma más rutinaria. Sin embargo, dada la gran cantidad de información obtenida se hacen necesarios el análisis y la interpretación adecuada de los resultados para garantizar un diagnóstico correcto. Este nuevo modelo de medicina amplía nuestra comprensión sobre estas patologías, gracias a que optimiza el diagnóstico, da una mejor aproximación pronóstica de los pacientes e identifica individuos asintomáticos en riesgo. Este artículo pretende realizar una revisión de la arquitectura genética de las enfermedades cardíacas hereditarias y proporcionar un enfoque práctico acerca de la utilidad de la Medicina genómica en el diagnóstico, la estratificación del riesgo y el estudio familiar en pacientes con este tipo de patologías. Abstract: The familial heart diseases are a group of diseases with high clinical and genomic heterogeneity. As they can be inherited and are associated with sudden death, it is recommended to perform a clinical and genetic study of the individual affected, as well as the family, in a specialised unit. The implementation of massive sequencing has meant that access to genetic studies is available in the most routine clinical practice. However, due to the large amount of information obtained, the results have to analysed and interpreted to ensure a correct diagnosis. This new medicine model widens the understanding of these diseases, as due to the diagnosis being optimised, it provides a more accurate prognosis for the patients, and identifies asymptomatic individuals at risk. A review is presented on the genetic architecture of heritable heart disease and provides a practical approach on the usefulness of Genomic Medicine in the diagnosis, risk stratification, and the familial study in patients with these types of heart diseases. Palabras clave: Miocardiopatías, Muerte súbita cardiaca, Asociación genotipo-fenotipo, Secuenciación masiva, Keywords: Cardiomyopathies, Sudden cardiac death, Genotype-phenotype association, Massive sequencin

Genética clínica de la anemia de Fanconi

La anemia de Fanconi (AF) es un síndrome hereditario raro, de patrón recesivo mayoritariamente autosómico. Clínicamente se caracteriza por presentar malformaciones congénitas, fallo de médula ósea progresivo, endocrinopatías, predisposición a cáncer e hipersensibilidad celular a agente inductores de enlaces cruzados en el DNA (ICL). Esta enfermedad puede ser causada por mutacions bialélicas en cualquiera de los16 genes que hasta la fecha se han identificado, por lo cual existen 16 grupos de complementación. El grupo de complementación más frecuente a nivel mundial es el FA-A (63%) y su espectro mutacional es altamente heterogeneo. En la población Española la frecuencia de este grupo de complementaciòn es mayor (77%) debido a su alta prevalencia en la población gitana española. En este estudio se ha continuado con el análisis mutacional de los pacientes FA-A españoles usando la estrategia de análisis de las mutaciones más comunes y se ha iniciado en paralelo el análisis mutacional de poblaciones AF de algunos países Latino-americanos usando dicha estrategia. Adicionalmente, se ha estudiado el fenotipo celular de pacientes Fanconi-like y otros pacientes con fenotipo celular similar incluyendo un ensayo de fragilidad cromosómica negativo. Por otra parte, se ha realizado un estudio a largo plazo de la evolución hematológica de pacientes AF con mosaicismo somático hematológico. Finalmente, se ha analizado la tasa de eficiencia del diagnóstico genético preimplantacional (DGP) con tipificación del antígeno leucocitario humano (HLA) en parejas con hijos afectos de AF. Estos resultados confirman que la estrategia de cribado mutacional realizado en pacientes FA-A españoles es eficiente para identificar el 51% de las mutaciones en pacientes españoles y sólo el 17% de las mutaciones en la población Latino-americana estudiada hasta el momento. La implementación de la secuenciación masiva del exoma es muy eficiente para el subtipaje de pacientes AF, especialmente para los subtipos menos frecuentes, de esta manera se han subtipado dos pacientes españoles (FA104: FA-Q y FA287: FA-J). Con respecto al análisis de los pacientes Fanconi-like se observó que tienen una sensibilidad celular intermedia a agentes inductores de ICLs asociado a un fenotipo clínico similar a AF. Interesantemente, células derivadas de pacientes deficientes en FAN1 presentan una sensibilidad celular intermedia a agentes inductores de ICLs pero no presentan un fenotipo hematológico de AF, lo cual descarta a FAN1 como un gen candidato para AF. Por otra parte, se ha observado una mejoría hematológica en la mayoría de los pacientes AF con mosaicismo somático, pero con casos excepcionales que son relevantes para la predicción de resultados de futuros ensayos de terapia génica. Los resultados moleculares sugieren que la evolución clínica en estos pacientes no sólo depende del nivel celular donde ocurrió la reversión mutacional, sino también de la edad biológica y el potencial proliferativo de la célula revertida. Finalmente, se ha encontrado una baja tasa de éxito en parejas con hijos afectos con AF sometidas a DGP con tipificación HLA, muy probablemente debido a la edad materna avanzadaFanconi anemia (FA) is a rare genetic disorder, which is mainly inherited with autosomal recessive pattern. Clinically it is characterized by congenital and endocrine abnormalities, bone marrow failure, cancer predisposition and cellular hypersensitivity to DNA interstrand crosslinking agents (ICL). This disease is caused by biallelic mutations in any of 16 genes that have been identified so far, leading to 16 complementation groups. FA-A is the most common complementation group (63%) and its mutational spectrum is highly heterogeneous. In the Spanish population, the frequency of this complementation group is even higher (77%) due to its high prevalence in the Spanish gypsy population. In this study, we have continued the mutational analysis of Spanish FA-A patients by analyzing the most common mutations, and we also have started the mutational analysis of FA populations of some Latin-American countries by this strategy. In addition, we have studied the cellular phenotype of Fanconi-like patients and others patients with similar cellular phenotype including a negative chromosome fragility test. On the other hand, we have performed a long-term retrospective study of the hematological evolution of FA patients having hematologic somatic mosaicism. Finally, we have analyzed the rate of efficiency of preimplantation genetic diagnosis (PGD) with human leukocyte antigen (HLA) in couples with affected FA children. The results confirm that the mutational screening strategy adopted in Spanish FA-A patients is efficient to identify 51% of mutations in Spanish patients but only 17% of Latin-American populations studied so far. The implementation of whole exome sequencing is an efficient strategy for FA subtyping, especially for infrequent subtypes, as we have done confirming two Spanish patients (FA104: FA-Q and FA287:FA-J). It was observed that Fanconi-like patients share intermediate cell sensitivity to ICLs associated with clinical phenotype similar to FA. Interestingly, patient derived FAN1-deficient cells have intermediate cell sensitivity to ICLs but do not have a FA hematological phenotype, disregarding FAN1 as a candidate gene for FA. On the other hand, we have usually observed hematological improvement in patients with somatic mosaicism, but with exceptional cases that are relevant to predict the outcome of future gene therapy trials. The molecular results suggest that the clinical course in these patients depends not only on the cellular level where mutational reversion occurred but also on the biological age and proliferative potential of the reversed cell. Finally, we have found a very low success rate in couples with affected children with FA undergoing PGD with HLA typing, most probably due to the advanced maternal age

A Novel Heterozygous Intronic Mutation in the FBN1 Gene Contributes to FBN1 RNA Missplicing Events in the Marfan Syndrome

Marfan syndrome (MFS) is an autosomal dominantly inherited connective tissue disorder, mostly caused by mutations in the fibrillin-1 (FBN1) gene. We, by using targeted next-generation sequence analysis, identified a novel intronic FBN1 mutation (the c.2678-15C>A variant) in a MFS patient with aortic dilatation. The computational predictions showed that the heterozygous c.2678-15C>A intronic variant might influence the splicing process by differentially affecting canonical versus cryptic splice site utilization within intron 22 of the FBN1 gene. RT-PCR and Western blot analyses, using FBN1 minigenes transfected into HeLa and COS-7 cells, revealed that the c.2678-15C>A variant disrupts normal splicing of intron 22 leading to aberrant 13-nt intron 22 inclusion, frameshift, and premature termination codon. Collectively, the results strongly suggest that the c.2678-15C>A variant could lead to haploinsufficiency of the FBN1 functional protein and structural connective tissue fragility in MFS complicated by aorta dilation, a finding that further expands on the genetic basis of aortic pathology

Genetic evaluation, familial screening and exercise

A prática de atividade física regular é benéfica para pessoas de todas as idades, gêneros e etnias.1 Se, por um lado, a prática do exercício moderado é considerada uma atividade saudável e favorável ao sistema cardiovascular, por outro, o exercício de alta intensidade por longo período de tempo pode aumentar o risco de morte súbita (MS).2 Mesmo considerando que um número imenso de pessoas faça exercício diariamente, a MS nesse cenário é considerada uma entidade rara. No entanto, a sua prevenção pode ser difícil e a mesma é de grande repercussão, principalmente quando incide em jovens praticantes de exercício recreativo ou em atletas. Do ponto de vista epidemiológico, a MS de origem cardíaca afeta entre 200 e 400 mil indivíduos nos Estados Unidos (EUA) anualmente.3 No âmbito dos esportes, estima-se que em torno de 200 atletas ao ano apresentem um evento fatal.4 Na Espanha, o registro nacional de MS em atletas descreveu 180 casos de 1995 até 2007, sugerindo uma incidência de 15 a 20 casos por ano.5 Em atletas, a avaliação pré-participação (APP) está indicada, podendo ser eficaz para a prevenção de MS cardíaca nesse contexto.6 Contudo, esse tipo de rastreamento apresenta grande variabilidade entre diferentes países e entidades que o realizam. No tocante à avaliação genética, essa se encontra relegada somente a casos específicos no contexto dos esportes. Nessa revisão descreveremos aspectos básicos da avaliação genética, assim como as indicações da análise molecular e sua correta interpretação clínica, tanto para esportistas recreativos ou amadores, quanto para os atletas de alto rendimento.Regular physical activity practice benefits individuals of all ages, sexes and ethnicities.1 If on one hand the practice of moderate exercise is considered a healthy activity that favors the cardiovascular system, on the other, high-intensity exercise for a long period can increase the risk for sudden death (SD).2 Even considering the huge number of individuals exercising daily, SD in that context is rare. However, the prevention of SD can be difficult and it has significant repercussion, mainly among young practitioners of leisure exercise or athletes. From the epidemiological viewpoint, cardiac SD affects 200,000 to 400,000 individuals in the United States of America (USA) annually.3 In the sports scenario, around 200 athletes per year are estimated to have a fatal event.4 In Spain, the national registry of SD in athletes reported 180 cases from 1995 to 2007, suggesting an incidence of 15 to 20 cases per year.5 For athletes, preparticipation evaluation (PPE) is indicated, and can be effective in preventing cardiac SD in that context.6 However, that type of screening has great variability between different countries and entities that perform it. In the sports context, genetic evaluation is performed only in specific cases. This review describes basic aspects of genetic evaluation, as well as the indications for molecular analysis and their correct clinical interpretation, for practitioners of recreational exercise, amateur sportsmen and high-performance athletes