ABSTRACT
Genetic counseling and genetic testing are essential for individuals with congenital heart disease/defects (CHD/CHDs). However, the clinical practices of genetic counselors (GCs) and their preferences for different CHD genetic testing strategies are previously unexplored. To address these gaps, GCs (n = 112) representing diverse specialties completed an online survey regarding their counseling and testing practices for syndromic CHD and apparently isolated/non-syndromic CHDs (iCHD). We found practice variability around family screening recommendations, with prenatal respondents reporting lower prevalence of this practice for iCHDs (p = 0.0004). We found that all specialties considered chromosomal microarray (CMA) the most common prioritized genetic test for syndromic and iCHD, while more prenatal respondents considered FISH and karyotype useful for iCHDs compared to postnatal respondents (p = 0.0002 and p = 0.002, respectively). Among postnatal respondents, a higher proportion considered exome/genome sequencing as useful compared to prenatal respondents (p = 0.0159); specifically, postnatal respondents' preference for exome/genome sequencing for iCHDs was ~2.6-fold higher than prenatal respondents. We estimated participants' assessment of utility for different genetic testing modalities for iCHDs and found that prenatal respondents assigned higher mean utility to FISH (p = 0.0002), karyotype (p = 0.0006), and CMA (p < 0.0001). There were relatively moderate to decreased utility scores for gene panels and exome/genome sequencing for iCHDs compared to cytogenetic testing, across all specialties. Overall, these results provide insight into GC practices and use of various genetic testing strategies for syndromic CHDs and iCHDs. Findings may help inform and/or standardize clinical practices for CHD genetic testing, though additional studies are warranted.
ABSTRACT
Cardiovascular genetic counseling has expanded as an established genetic counseling specialty over the last 20 years. Despite guidelines recommending genetic counseling for heritable cardiac diseases, there have been limited descriptions of the practice model types used for different clinical indications seen in this genetic counseling subspecialty. We aimed to describe current clinical practice models used by cardiovascular genetic counselors and to document practice model strengths, challenges, and areas for improvement. Genetic counselor respondents (n = 63) who self-reported seeing cardiovascular indications were recruited through the National Society of Genetic Counselors and Twitter. They completed a survey describing the types of healthcare professionals with whom they collaborate to see common cardiovascular indications, the nature of their collaboration, and their qualitative experiences with their practice models. Clinical indications addressed in this survey were hypertrophic cardiomyopathy, dilated cardiomyopathy, all other cardiomyopathies, arrhythmias, aortopathies, dyslipidemias, pulmonary arterial hypertension, and congenital heart defects. Data were analyzed using descriptive statistics and thematic analysis. We found that the composition of multidisciplinary provider practice models varies by indication, though general cardiologists were the most common collaborative provider reported. Practice models including geneticists were most common for aortopathy indications. Overall, the majority of respondents were satisfied with the practice models they reported. While a wide variety of successes, challenges, and areas for improvement of practice models were reported, collaboration, communication, and access to appropriate providers for patient care were consistent themes across these three questions. To our knowledge, this is the first description of practice models used by cardiovascular genetic counselors. The results of this study add to the knowledge of this specialty of genetic counseling and assist in understanding the needs and challenges for developing cardiovascular genetics programs and clinics.
Subject(s)
Cardiovascular Diseases , Genetic Counseling , Humans , Counselors , Health Personnel , North America , Practice Guidelines as Topic , Cross-Sectional Studies , Surveys and QuestionnairesABSTRACT
The COVID-19 pandemic required genetic counseling services, like most outpatient healthcare, to rapidly adopt a telemedicine model. Understanding the trends in patients' preferences for telemedicine relative to in-person service delivery both before and after the advent of the COVID-19 pandemic may aid in navigating how best to integrate telemedicine in a post-COVID-19 era. Our study explored how respondents' willingness to use, and preference for, telemedicine differed from before to after the onset of the COVID-19 pandemic. Respondents included patients, or their parent/guardian, seen in a general medical genetics clinic in 2018, prior to the COVID-19 pandemic, and in 2021, during the COVID-19 pandemic. Respondents were surveyed regarding their willingness to use telemedicine, preference for telemedicine relative to in-person care, and the influence of various factors. Among 69 pre-COVID-19 and 40 current-COVID-19 respondents, there was no shift in willingness to use, or preference for, telemedicine across these time periods. About half of respondents (50.6%) preferred telemedicine visits for the future. Of the 49.4% who preferred in-person visits, 79.1% were still willing to have visits via telemedicine. Predictors of these preferences included comfort with technology and prioritization of convenience of location. This study suggests that a hybrid care model, utilizing telemedicine and in-person service delivery, may be most appropriate to meet the needs of the diverse patients served. Concern for COVID-19 was not found to predict willingness or preference, suggesting that our findings may be generalizable in post-pandemic contexts.
ABSTRACT
Congenital heart disease (CHD) is a common group of birth defects with a strong genetic contribution to their etiology, but historically the diagnostic yield from exome studies of isolated CHD has been low. Pleiotropy, variable expressivity, and the difficulty of accurately phenotyping newborns contribute to this problem. We hypothesized that performing exome sequencing on selected individuals in families with multiple members affected by left-sided CHD, then filtering variants by population frequency, in silico predictive algorithms, and phenotypic annotations from publicly available databases would increase this yield and generate a list of candidate disease-causing variants that would show a high validation rate. In eight of the nineteen families in our study (42%), we established a well-known gene/phenotype link for a candidate variant or performed confirmation of a candidate variant's effect on protein function, including variants in genes not previously described or firmly established as disease genes in the body of CHD literature: BMP10, CASZ1, ROCK1 and SMYD1. Two plausible variants in different genes were found to segregate in the same family in two instances suggesting oligogenic inheritance. These results highlight the need for functional validation and demonstrate that in the era of next-generation sequencing, multiplex families with isolated CHD can still bring high yield to the discovery of novel disease genes.
Subject(s)
Exome , Heart Defects, Congenital , Bone Morphogenetic Proteins/genetics , DNA-Binding Proteins/genetics , Exome/genetics , Gene Frequency , Genetic Association Studies , Heart Defects, Congenital/genetics , Humans , Infant, Newborn , Pedigree , Transcription Factors/genetics , Exome Sequencing , rho-Associated Kinases/geneticsABSTRACT
Genetic counselors are one of the many providers involved in caring for patients with congenital heart defects (CHDs); however, little is known about the cardiovascular genetics training they receive by their graduate programs. To explore the recalled education experiences regarding CHDs by practicing genetic counselors, we surveyed graduates of programs primarily accredited by the American Council on Genetic Counseling (ACGC) about their graduate training in this area, the depth of CHD-specific education they received, and whether CHDs are a substantial referral indication in their current practice. Genetic counselors were recruited from the National Society of Genetic Counselors and Twitter (n = 112), and participants reflecting multiple specialties and 35 graduate programs completed an online survey which included questions about fieldwork placements and lectures in cardiovascular genetics, exposure to classification schemes regarding cardiac embryology, and education in counseling strategies for CHDs and CHD-related topics during their graduate training. When asked whether CHDs are a substantial referral indication seen in their current practice, 55% (62/112) responded yes. Most participants (79%, 88/112) recalled receiving some education about CHDs, but 91% (80/88) reported receiving little to no education regarding embryologic classification of CHDs and how to apply classification schemes to their counseling. Both participating prenatal and pediatric GCs reported that CHDs can be a common referral indication, yet they reported receiving limited education on teratogens associated with CHDs, family screening recommendations, and recurrence risk counseling for CHDs. Based on participant responses, the majority of respondents reported receiving sufficient education on syndromes with CHDs which can be beneficial in specialties such as pediatrics. This exploratory study provides insight into opportunities to further support genetic counseling educational opportunities for CHDs. These findings suggest genetic counseling graduate programs could consider implementing education on CHD counseling strategies as a standardized component of the curriculum and that practicing genetic counselors could benefit from educational opportunities and resources with updated information on this topic.
Subject(s)
Counselors , Heart Defects, Congenital , Child , Counseling , Counselors/psychology , Education, Graduate , Female , Genetic Counseling/psychology , Humans , Pregnancy , United StatesABSTRACT
For the past two decades, the guidelines put forth by the American College of Medical Genetics and Genomics (ACMG) detailing providers' clinical responsibility to recontact patients have remained mostly unchanged, despite evolving variant interpretation practices which have yielded substantial rates of reclassification and amended reports. In fact, there is little information regarding genetic counselors' roles in informing patients of reclassified variants, or the process by which these amended reports are currently being handled. In this study, we developed a survey to measure current experiences with amended variant reports and preferences for ideal management, which was completed by 96 genetic counselors from the United States and Canada. All respondents indicated they were the individuals responsible for disclosing initial positive genetic testing results and any clinically actionable reclassified variant reports, and over half (56%) received at least a few amended variant reports each year. Nearly a quarter (20/87) of respondents reported having a standard operating procedure (SOP) for managing amended reports and all were very satisfied (12/20) or satisfied (8/20) with the SOP. Of those without a protocol, 76% (51/67) would prefer to have an SOP implemented. Respondents reported a preference for (1) laboratories to send amended variant reports directly to the genetic counselor or ordering physician through email or an online portal, and (2) notification to patients ideally occurring through a phone call. In the event that the original genetic counselor is inaccessible, respondents reported a preference for reports to be sent directly to another genetic counselor (36%) on the team or the clinic in general (27%). Information from this study provides insight into the current practices of genetic counselors as applied to amended reports and what improvements may increase the efficiency of the reporting process. Moreover, these results suggest a need for an updated statement addressing duty to recontact, specifically as it applies to amended variant reports.
Subject(s)
Counselors , Duty to Recontact , Genetic Counseling/methods , Genetic Testing , Humans , Surveys and Questionnaires , United StatesABSTRACT
Congenital heart disease (CHD) is an indication which spans multiple specialties across various genetic counseling practices. This practice resource aims to provide guidance on key considerations when approaching counseling for this particular indication while recognizing the rapidly changing landscape of knowledge within this domain. This resource was developed with consensus from a diverse group of certified genetic counselors utilizing literature relevant for CHD genetic counseling practice and is aimed at supporting genetic counselors who encounter this indication in their practice both pre- and postnatally.
Subject(s)
Counselors , Heart Defects, Congenital , Certification , Counseling , Counselors/psychology , Genetic Counseling/psychology , Heart Defects, Congenital/genetics , HumansABSTRACT
Hypertrophic cardiomyopathy (HCM) is characterized by thickening of the ventricular muscle without dilation and is often associated with dominant pathogenic variants in cardiac sarcomeric protein genes. Here, we report a family with two infants diagnosed with infantile-onset HCM and mitral valve dysplasia that led to death before one year of age. Using exome sequencing, we discovered that one of the affected children had a homozygous frameshift variant in Myosin light chain 2 (MYL2:NM_000432.3:c.431_432delCT: p.Pro144Argfs*57;MYL2-fs), which alters the last 20 amino acids of the protein and is predicted to impact the most C-terminal of the three EF-hand domains in MYL2. The parents are unaffected heterozygous carriers of the variant and the variant is absent in control cohorts from gnomAD. The absence of the phenotype in carriers and the infantile presentation of severe HCM is in contrast to HCM associated with dominant MYL2 variants. Immunohistochemical analysis of the ventricular muscle of the deceased patient with the MYL2-fs variant showed a marked reduction of MYL2 expression compared to an unaffected control. In vitro overexpression studies further indicate that the MYL2-fs variant is actively degraded. In contrast, an HCM-associated missense variant (MYL2:p.Gly162Arg) and three other MYL2 stop-gain variants (p.E22*, p.K62*, p.E97*) that result in loss of the EF domains are stably expressed but show impaired localization. The degradation of the MYL2-fs can be rescued by inhibiting the cell's proteasome function supporting a post-translational effect of the variant. In vivo rescue experiments with a Drosophila MYL2-homolog (Mlc2) knockdown model indicate that neither the MYL2-fs nor the MYL2:p.Gly162Arg variant supports normal cardiac function. The tools that we have generated provide a rapid screening platform for functional assessment of variants of unknown significance in MYL2. Our study supports an autosomal recessive model of inheritance for MYL2 loss-of-function variants in infantile HCM and highlights the variant-specific molecular differences found in MYL2-associated cardiomyopathy.
Subject(s)
Cardiac Myosins/genetics , Cardiomyopathy, Hypertrophic/genetics , Family , Frameshift Mutation , Myosin Light Chains/genetics , Adult , Animals , Animals, Genetically Modified , Cardiomyopathy, Hypertrophic/classification , Cardiomyopathy, Hypertrophic/congenital , Cardiomyopathy, Hypertrophic/pathology , Cells, Cultured , Consanguinity , Drosophila , Fatal Outcome , Female , Genes, Dominant , Genes, Recessive , Heterozygote , Humans , Infant , Infant Death , Infant, Newborn , Male , Pedigree , Phenotype , SiblingsABSTRACT
Genetic testing is important to augment clinical diagnosis and inform management of inherited arrhythmias syndromes (IAS), but variants of uncertain significance (VUS) are common and remain a challenge in clinical practice. In 2015, American College of Medical Genetics (ACMG) published updated guidelines for interpretation of genetic results. Despite increasing understanding of human genomic variation, there are no guidelines for reinterpretation of prior genetic test results. Patients at a single tertiary children's hospital with genetic testing for an IAS that demonstrated a VUS were re-evaluated using 2015 ACMG guidelines, clinical information, and publically available databases. Search of the electronic medical record identified 116 patients with genetic testing results available, and 24/116 (21%) harbored a VUS for an IAS. 23 unique VUS were evaluated from 12 genes. Over half of the VUS (12/23 (52%)) were reclassified using 2015 criteria, and 8 (35%) changed to pathogenic and 4 (17%) to benign. Relative risk of reclassification of VUS to a pathogenic variant in a patient with confirmed clinical diagnosis was 4.1 (95% CI 1.23-15.4). Reclassification was not associated with initial testing year. These data demonstrate 52% of VUS in children with IAS are reclassified with application of 2015 ACMG guidelines. Strength of phenotyping is associated with eventual pathogenic classification of genetic variants and periodic re-evaluation of VUS identified on genetic testing for IAS is warranted.
Subject(s)
Arrhythmias, Cardiac/genetics , Genetic Predisposition to Disease , Genetic Testing/standards , Adolescent , Child , Child, Preschool , Female , Genetic Testing/methods , Humans , Infant , Male , Practice Guidelines as Topic , Retrospective Studies , SyndromeABSTRACT
The evidence base supporting genetic and genomic sequence-variant interpretations is continuously evolving. An inherent consequence is that a variant's clinical significance might be reinterpreted over time as new evidence emerges regarding its pathogenicity or lack thereof. This raises ethical, legal, and financial issues as to whether there is a responsibility to recontact research participants to provide updates on reinterpretations of variants after the initial analysis. There has been discussion concerning the extent of this obligation in the context of both research and clinical care. Although clinical recommendations have begun to emerge, guidance is lacking on the responsibilities of researchers to inform participants of reinterpreted results. To respond, an American Society of Human Genetics (ASHG) workgroup developed this position statement, which was approved by the ASHG Board in November 2018. The workgroup included representatives from the National Society of Genetic Counselors, the Canadian College of Medical Genetics, and the Canadian Association of Genetic Counsellors. The final statement includes twelve position statements that were endorsed or supported by the following organizations: Genetic Alliance, European Society of Human Genetics, Canadian Association of Genetic Counsellors, American Association of Anthropological Genetics, Executive Committee of the American Association of Physical Anthropologists, Canadian College of Medical Genetics, Human Genetics Society of Australasia, and National Society of Genetic Counselors.
Subject(s)
Duty to Recontact , Duty to Warn/legislation & jurisprudence , Genetic Testing/standards , Genetics, Medical/standards , Genomics/standards , Australia , Canada , Ethics, Research , Europe , Genetics, Medical/education , Genetics, Medical/ethics , Humans , Liability, Legal , Research Subjects , Societies, Medical , United StatesABSTRACT
Bicuspid aortic valve (BAV) is the most common type of congenital heart defect (CHD) and is associated with clinically significant cardiovascular complications including valve calcification and ascending aortopathy (AscAo), predominantly occurring in adulthood. While a limited number of genetic etiologies for BAV have been defined, family members of affected individuals display BAV along with other left-sided CHD. This has led to guidelines from the American Heart Association and American College of Cardiology that recommend echocardiographic screening of first-degree relatives of affected adults. While potentially beneficial in adults, the yield of such screening in children is unknown. The purpose of this study was to investigate a cohort of children with familial BAV to determine the frequency of development of AscAo, and to identify risk factors that contribute to abnormal aortic growth. Echocardiograms over a 10-year follow-up period were reviewed on 26 patients with familial BAV [22 male, 4 female; 22 with isolated BAV, 6 with BAV and aortic coarctation (CoA)]. All had a family history of CHD and were recruited from 2005 to 2010 as part of a genetics research study. Four aortic segments (annulus, root, sinotubular junction, ascending aorta) on parasternal long-axis echocardiographic images were measured by a single observer. The mean age at first echocardiogram was 7.1 ± 5.5 and that was 13.8 ± 6.2 years at the last echocardiogram. Only patients with > 2 echocardiograms in the 10-year period were included. Z score measurements of the aorta were plotted over time and based on these the cohort was divided into two groups: Group 1 (abnormal)-Z score for any segment > 2 or a change in Z score > 2 over follow-up; Group 2 (normal)-Z score < 2 throughout follow-up and change in Z score < 2. Nineteen out of 26 children displayed abnormal aortic growth or dilation of the aorta. BAV with right/left cusp fusion was more frequent in Group 1 (15/18) versus Group 2 (3/7) (p < 0.05). There were no significant differences in gender, aortic valve dysfunction, presence of CoA, family history, cardiac function, presence of left ventricular hypertrophy, or medication use between the 2 groups. In our longitudinal study of children with familial BAV, the majority display evidence of abnormal growth of the ascending aorta during the follow-up period consistent with AscAo and support the extension of current adult guidelines to the pediatric population. While we find that right/left cusp fusion is a risk factor for abnormal aortic growth, additional studies are needed to identify other factors to better select children who require serial screening.
Subject(s)
Aorta/growth & development , Aortic Diseases/etiology , Aortic Valve/abnormalities , Heart Valve Diseases/complications , Adolescent , Adult , Aorta/diagnostic imaging , Aorta/pathology , Aortic Diseases/diagnostic imaging , Aortic Valve/diagnostic imaging , Bicuspid Aortic Valve Disease , Child , Child, Preschool , Echocardiography/methods , Female , Follow-Up Studies , Heart Valve Diseases/diagnostic imaging , Humans , Longitudinal Studies , Male , Mass Screening/methods , Risk Factors , Young AdultABSTRACT
Marfan syndrome is a multisystem disease with cardiovascular, ophthalmologic, and skeletal features. Diagnosis is made clinically with emphasis on presence of aortic root dilation and ectopia lentis (EL). Most individuals meeting these criteria have a pathogenic variant in FBN1, usually unique or observed rarely. Individuals with EL alone may also have FBN1 pathogenic variants, and the risk for aortic disease is not well known. We identified a unique cohort of 31 individuals (mean age 29, range 2-78) from nine families ascertained by a proband with EL alone, who had the same FBN1 p.R650C variant. Comparison was made to individuals with Marfan syndrome (n = 103 from 97 families) at our institution. Those with the p.R650C variant had few skeletal features of Marfan syndrome. Age of onset of EL was later compared to others with cysteine variant changes. Aortic root dilation occurred in 4/16 (25%) of the p.R650C group versus 71/83 (86%) in the comparator group (p < 0.001) and dissection or replacement in 1/31 (3%) versus 20/103 (19%; p < 0.04). Aortic root Z scores were much lower in the p.R650C (0.34 ± 1.70) versus the comparator (2.99 ± 2.54; p < 0.0002). Kaplan-Meier failure curves for aortic root dilation demonstrated later age of onset and differed significantly for incidence rate ratio (comparator vs. p.R650C = 5.35, CI 1.84-21.17; p = 0.0001). Individuals with p.R650C predominantly have EL, but do have risk for aortic dilation at ages later than typical for Marfan syndrome in general and for cysteine changes specifically. Surveillance for aortic dilation is required but may occur less frequently.
Subject(s)
Aortic Diseases/genetics , Ectopia Lentis/genetics , Fibrillin-1/genetics , Adolescent , Adult , Aged , Aortic Diseases/physiopathology , Child , Child, Preschool , Ectopia Lentis/physiopathology , Female , Genotype , Humans , Male , Marfan Syndrome/genetics , Marfan Syndrome/physiopathology , Middle Aged , Mutation , Pedigree , Phenotype , Polymorphism, Single Nucleotide , Risk Factors , Young AdultABSTRACT
Congenital left-sided cardiac lesions (LSLs) are a significant contributor to the mortality and morbidity of congenital heart disease (CHD). Structural copy number variants (CNVs) have been implicated in LSL without extra-cardiac features; however, non-penetrance and variable expressivity have created uncertainty over the use of CNV analyses in such patients. High-density SNP microarray genotyping data were used to infer large, likely-pathogenic, autosomal CNVs in a cohort of 1,139 probands with LSL and their families. CNVs were molecularly confirmed and the medical records of individual carriers reviewed. The gene content of novel CNVs was then compared with public CNV data from CHD patients. Large CNVs (>1 MB) were observed in 33 probands (â¼3%). Six of these were de novo and 14 were not observed in the only available parent sample. Associated cardiac phenotypes spanned a broad spectrum without clear predilection. Candidate CNVs were largely non-recurrent, associated with heterozygous loss of copy number, and overlapped known CHD genomic regions. Novel CNV regions were enriched for cardiac development genes, including seven that have not been previously associated with human CHD. CNV analysis can be a clinically useful and molecularly informative tool in LSLs without obvious extra-cardiac defects, and may identify a clinically relevant genomic disorder in a small but important proportion of these individuals.
Subject(s)
DNA Copy Number Variations/genetics , Heart Defects, Congenital/genetics , Heart/physiopathology , Adolescent , Adult , Child , Child, Preschool , Female , Genetic Association Studies , Genomics , Genotype , Heart Defects, Congenital/physiopathology , Humans , Infant , Infant, Newborn , Male , Middle Aged , Phenotype , Polymorphism, Single Nucleotide , Young AdultABSTRACT
The increased adoption of clinical whole exome sequencing (WES) has improved the diagnostic yield for patients with complex genetic conditions. However, the informatics practice for handling information contained in whole exome reports is still in its infancy, as evidenced by the lack of a common vocabulary within clinical sequencing reports generated across genetic laboratories. Genetic testing results are mostly transmitted using portable document format, which can make secondary analysis and data extraction challenging. This paper reviews a sample of clinical exome reports generated by Clinical Laboratory Improvement Amendments-certified genetic testing laboratories at tertiary-care facilities to assess and identify common data elements. Like structured radiology reports, which enable faster information retrieval and reuse, structuring genetic information within clinical WES reports would help facilitate integration of genetic information into electronic health records and enable retrospective research on the clinical utility of WES. We identify elements listed as mandatory according to practice guidelines but are currently missing from some of the clinical reports, which might help to organize the data when stored within structured databases. We also highlight elements, such as patient consent, that, although they do not appear within any of the current reports, may help in interpreting some of the information within the reports. Integrating genetic and clinical information would assist the adoption of personalized medicine for improved patient care and outcomes.
Subject(s)
Common Data Elements , Exome , Genetic Testing , Laboratories/standards , Research Report/standards , Sequence Analysis, DNA , Guidelines as Topic , HumansABSTRACT
In the last decade, an increasing number of cardiac conditions have been shown to have a genetic basis. Cardiovascular genetic counseling has emerged as a subspecialty aiming to identify unaffected at-risk individuals. An important sector of this at-risk population also includes expectant mothers, in whom unique clinical challenges may arise. Genetic counselors, especially those in cardiovascular and prenatal settings, have an opportunity to identify and assist women who may benefit from cardiovascular care during pregnancy. This paper provides basic management and genetic evaluation principles for affected women, as well as guidance on identifying those who are at risk. We provide considerations for cardiac surveillance in pregnancy and the post-partum period. Finally, key psychosocial issues that appraise how to best provide support to at risk women as they make informed decisions are discussed. We propose that a team approach including cardiology, maternal fetal medicine, and genetic counseling best serves this patient population. Ongoing questions addressing an evidence based approach to cardiovascular genetic conditions in pregnancy still remain. Thus, well-designed research protocols are essential to mark progress in this area.
Subject(s)
Cardiovascular Diseases/congenital , Cardiovascular Diseases/diagnosis , Counselors/standards , Genetic Counseling/standards , Pregnancy Complications, Cardiovascular/diagnosis , Prenatal Diagnosis/standards , Adult , Female , Humans , Pregnancy , Risk FactorsABSTRACT
BACKGROUND: Congenital heart disease (CHD) is the most common type of birth defect with family- and population-based studies supporting a strong genetic cause for CHD. The goal of this study was to determine whether a whole exome sequencing (WES) approach could identify pathogenic-segregating variants in multiplex CHD families. METHODS AND RESULTS: WES was performed on 9 kindreds with familial CHD, 4 with atrial septal defects, 2 with patent ductus arteriosus, 2 with tetralogy of Fallot, and 1 with pulmonary valve dysplasia. Rare variants (<1% minor allele frequency) that segregated with disease were identified by WES, and variants in 69 CHD candidate genes were further analyzed. These selected variants were subjected to in silico analysis to predict pathogenicity and resulted in the discovery of likely pathogenic mutations in 3 of 9 (33%) families. A GATA4 mutation in the transactivation domain, p.G115W, was identified in familial atrial septal defects and demonstrated decreased transactivation ability in vitro. A p.I263V mutation in TLL1 was identified in an atrial septal defects kindred and is predicted to affect the enzymatic functionality of TLL1. A disease-segregating splice donor site mutation in MYH11 (c.4599+1delG) was identified in familial patent ductus arteriosus and found to disrupt normal splicing of MYH11 mRNA in the affected individual. CONCLUSIONS: Our findings demonstrate the clinical utility of WES to identify causative mutations in familial CHD and demonstrate the successful use of a CHD candidate gene list to allow for a more streamlined approach enabling rapid prioritization and identification of likely pathogenic variants from large WES data sets. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov; Unique Identifier: NCT0112048.
Subject(s)
Exome , Heart Defects, Congenital/genetics , Mutation , Adolescent , Cells, Cultured , Child , Child, Preschool , Computer Simulation , DNA Mutational Analysis/methods , Databases, Genetic , Ductus Arteriosus, Patent/diagnosis , Ductus Arteriosus, Patent/genetics , Female , GATA4 Transcription Factor/genetics , Gene Frequency , Genetic Markers , Genetic Predisposition to Disease , Genome-Wide Association Study , Heart Defects, Congenital/diagnosis , Heart Defects, Congenital/therapy , Heart Septal Defects, Atrial/diagnosis , Heart Septal Defects, Atrial/genetics , Heredity , High-Throughput Nucleotide Sequencing , Humans , Infant , Male , Models, Genetic , Mutation Rate , Myosin Heavy Chains/genetics , Pedigree , Phenotype , Risk Factors , Tetralogy of Fallot/diagnosis , Tetralogy of Fallot/genetics , Tolloid-Like Metalloproteinases/geneticsABSTRACT
Congenital heart defects involving left-sided lesions (LSLs) are relatively common birth defects with substantial morbidity and mortality. Previous studies have suggested a high heritability with a complex genetic architecture, such that only a few LSL loci have been identified. We performed a genome-wide case-control association study to address the role of common variants using a discovery cohort of 778 cases and 2756 controls. We identified a genome-wide significant association mapping to a 200 kb region on chromosome 20q11 [P= 1.72 × 10-8 for rs3746446; imputed Single Nucleotide Polymorphism (SNP) rs6088703 P= 3.01 × 10-9, odds ratio (OR)= 1.6 for both]. This result was supported by transmission disequilibrium analyses using a subset of 541 case families (lowest P in region= 4.51 × 10-5, OR= 1.5). Replication in a cohort of 367 LSL cases and 5159 controls showed nominal association (P= 0.03 for rs3746446) resulting in P= 9.49 × 10-9 for rs3746446 upon meta-analysis of the combined cohorts. In addition, a group of seven SNPs on chromosome 1q21.3 met threshold for suggestive association (lowest P= 9.35 × 10-7 for rs12045807). Both regions include genes involved in cardiac development-MYH7B/miR499A on chromosome 20 and CTSK, CTSS and ARNT on chromosome 1. Genome-wide heritability analysis using case-control genotyped SNPs suggested that the mean heritability of LSLs attributable to common variants is moderately high ([Formula: see text] range= 0.26-0.34) and consistent with previous assertions. These results provide evidence for the role of common variation in LSLs, proffer new genes as potential biological candidates, and give further insight to the complex genetic architecture of congenital heart disease.
Subject(s)
Chromosomes, Human, Pair 20/genetics , Genetic Predisposition to Disease , Genome-Wide Association Study , Heart Defects, Congenital/genetics , Chromosome Mapping , Cohort Studies , Female , Genotype , Heart Defects, Congenital/physiopathology , Heart Ventricles/physiopathology , Humans , Male , Polymorphism, Single NucleotideABSTRACT
Dilated cardiomyopathy (DCM) is a disease of the myocardium characterized by left ventricular dilatation and diminished contractile function. Here we describe a novel DCM mutation in the myosin regulatory light chain (RLC), in which aspartic acid at position 94 is replaced by alanine (D94A). The mutation was identified by exome sequencing of three adult first-degree relatives who met formal criteria for idiopathic DCM. To obtain insight into the functional significance of this pathogenic MYL2 variant, we cloned and purified the human ventricular RLC wild-type (WT) and D94A mutant proteins, and performed in vitro experiments using RLC-mutant or WT-reconstituted porcine cardiac preparations. The mutation induced a reduction in the α-helical content of the RLC, and imposed intra-molecular rearrangements. The phosphorylation of RLC by Ca²âº/calmodulin-activated myosin light chain kinase was not affected by D94A. The mutation was seen to impair binding of RLC to the myosin heavy chain, and its incorporation into RLC-depleted porcine myosin. The actin-activated ATPase activity of mutant-reconstituted porcine cardiac myosin was significantly higher compared with ATPase of wild-type. No changes in the myofibrillar ATPase-pCa relationship were observed in wild-type- or D94A-reconstituted preparations. Measurements of contractile force showed a slightly reduced maximal tension per cross-section of muscle, with no change in the calcium sensitivity of force in D94A-reconstituted skinned porcine papillary muscle strips compared with wild-type. Our data indicate that subtle structural rearrangements in the RLC molecule, followed by its impaired interaction with the myosin heavy chain, may trigger functional abnormalities contributing to the DCM phenotype.
Subject(s)
Cardiac Myosins/genetics , Cardiomyopathy, Dilated/genetics , Mutation , Myosin Light Chains/genetics , Actins/metabolism , Adenosine Triphosphatases/chemistry , Adenosine Triphosphatases/genetics , Adenosine Triphosphatases/metabolism , Adult , Amino Acid Substitution , Animals , Cardiac Myosins/chemistry , Cardiac Myosins/metabolism , Cardiomyopathy, Dilated/metabolism , Circular Dichroism , DNA Mutational Analysis , Female , Humans , Male , Myosin Heavy Chains/chemistry , Myosin Heavy Chains/metabolism , Myosin Light Chains/chemistry , Myosin Light Chains/metabolism , Pedigree , Protein Conformation , Protein Structure, Secondary , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sus scrofaABSTRACT
PURPOSE: Because of the increased risks associated with unplanned pregnancy for males and females with congenital heart disease (CHD), we investigated sexual intercourse and contraception use in these adolescents and young adults (AYA) and compared the same with national and state population data. METHODS: We recruited 337 AYA with structural CHD aged 15-25 years (Mage = 19 years, standard deviation = 3.1; 53% male, 84% white) from an outpatient cardiology clinic to participate in a larger study assessing genetic knowledge and health behaviors. Cumulative lifetime prevalence of adolescent (aged 15-18 years) sexual intercourse was compared with the 2011 Youth Risk Behavior Surveillance System and the 2007 Ohio Youth Risk Behavior Survey. Cumulative lifetime prevalence of young adult (aged 19-25 years) sexual intercourse and contraception use at last sex were compared with the 2006-2008 National Survey of Family Growth. RESULTS: Reported rates of ever having sexual intercourse, 26% of adolescents and 74% of young adults with CHD, were significantly lower than general population rates (47% and 86% respectively; p < .001). Similar to the general population, 77% of previously sexually active young adults with CHD reported using at least one effective method of contraception at last intercourse, whereas 25% used dual effective methods and 23% used no effective method. CONCLUSIONS: Lower rates of ever having sexual intercourse in this population suggest that the psychosexual development of AYA with CHD may lag behind their peers. As nearly one in four participants reported using no effective method of contraception, health care providers should increase discussions of contraception with males and females with CHD.