Genetic testing for familial hypertrophic cardiomyopathy in newborn infants

Molecular genetics in hypertrophic cardiomyopathy: towards individualized management of the disease

Hypertrophic cardiomyopathy is a relatively common genetic disease, affecting one person per 500 in the general population, and is clinically defined by the presence of unexplained left ventricular hypertrophy. Although recognized as the most common cause of sudden death in the young (especially in athletes), the cardiac expression of the disease is highly variable with respect to age at onset, degree of symptoms and risk of cardiac death. As a consequence, therapeutic strategies are diverse and must be adapted to the specific features of an individual. Recently, the molecular bases of the disease have been unraveled with the identification of a large number of mutations in genes encoding sarcomeric proteins. This review focuses on the impact of the molecular data on the understanding of the disease, and considers the emerging issues regarding the impact of molecular testing on the management of patients (or relatives) in clinical practice.

Left ventricular hypertrophy is prevalent in Sprague-Dawley rats

Unrecognized cardiovascular abnormalities may confound the interpretation of research data collected using rats. However, although SPF rat colonies are screened for microbes and kept under standardized environmental conditions, their cardiovascular status is largely unknown. We recently performed surgery on anesthetized 80-d-old Sprague-Dawley rats and observed a high mortality that could not be attributed to the procedures or preceding treatments. Upon necropsy, cardiomyopathy was readily apparent in a substantial proportion of these rats. To further evaluate the nature of this condition, we evaluated the histology and morphology of hearts from both Sprague-Dawley and Lewis rats. Compared with Lewis rats, Sprague-Dawley rats had greater left ventricular wall thickness and larger cardiomyocyte cell size. Severe left ventricle hypertrophy was present in 38% of young adult Sprague-Dawley rats. These findings may have implications for research models that use Sprague-Dawley rats.

Genetic counselling and testing in cardiomyopathies: a position statement of the European Society of Cardiology Working Group on Myocardial and Pericardial Diseases

Advances in molecular genetics present new opportunities and challenges for cardiologists who manage patients and families with cardiomyopathies. The aims of this position statement of the European Society of Cardiology Working Group on Myocardial and Pericardial Diseases are to review the general issues related to genetic counselling, family screening and genetic testing in families with a cardiomyopathy, and to provide key messages and suggestions for clinicians involved in their management.

Parental knowledge and attitudes toward hypertrophic cardiomyopathy genetic testing

Hypertrophic cardiomyopathy (HCM) is a common autosomal dominant condition with an increased risk of sudden cardiac death. Although clinical genetic testing can be used for confirmation of a clinical diagnosis as well as a predictive test, based on our clinical experience it is underutilized. Therefore, we developed and administered a questionnaire to assess potential determinants of parental interest in this testing. Of the 30 adult caregivers who participated, 80% had heard of genetic testing, whereas only 30% knew about genetic testing specifically for HCM. Once informed of the availability, 62% said they would consider testing in the future and 28% would consider it in the next year. Participants' younger age, higher education level, knowledge of carrier testing, and positive view of genetic testing were significantly associated with the participant considering HCM genetic testing for their child (p <or= 0.05). Based on a logistic regression model, age, education level, and knowing that HCM is an inherited disease were the best predictors of who would consider genetic testing. This study provides healthcare providers with a framework to understand caregivers' knowledge and views of genetic testing, which can be used to improve clinical care for pediatric HCM patients.

Familial screening and genetic counselling in hypertrophic cardiomyopathy: the Rotterdam experience

Hypertrophic cardiomyopathy (HCM) is a disease characterised by unexplained left ventricular hypertrophy (LVH) (i.e. LVH in the absence of another cardiac or systemic disease that could produce a similar degree of hypertrophy), electrical instability and sudden death (SD).Germline mutations in genes encoding for sarcomere proteins are found in more than half of the cases of unexplained LVH. The autosomal dominant inherited forms of HCM are characterised by incomplete penetrance and variability in clinical and echocardiographic features, prognosis and therapeutic modalities. The identification of the genetic defect in one of the HCM genes allows accurate presymptomatic detection of mutation carriers in a family. Cardiac evaluation of at-risk relatives enables early diagnosis and identification of those patients at high risk for SD, which can be the first manifestation of the disease in asymptomatic persons.In this article we present our experience with genetic testing and cardiac screening in our HCM population and give an overview of the current literature available on this subject. (Neth Heart J 2007;15:184-9.).

Counselling issues in familial hypertrophic cardiomyopathy

To illustrate the variable clinical presentations and rates of progression in familial hypertrophic cardiomyopathy (FHC), phenotypes and genotypes were compared in three FHC families with different genetic defects. In the first family, the FHC abnormality was a protein truncating mutation (Gln969X) in the cardiac myosin binding protein C gene. The second family had a missense change (Asn755Lys) in the same gene. A missense mutation (Arg453Cys) in the cardiac beta myosin heavy chain gene was present in the third family. Penetrance associated with the Gln969X defect was 27% in the age range 0 to 40 years. This was considerably less than the 93% penetrance (0 to 40 years) observed in the two families with missense mutations. The variable penetrance in FHC, as well as the unpredictability of sudden cardiac death, complicates clinical diagnosis and management, including genetic counselling. Although a genetic disease with a predominantly adult onset, there are counselling issues in FHC which set it aside from other adult onset disorders.

Eugenics and the new genetics in Britain: examining contemporary professionals' accounts

This article explores the accounts of eugenics made by a small but important group of British scientists and clinicians working on the new genetics as applied to human health. These scientists and clinicians used special rhetorical strategies for distancing the new genetics from eugenics and to sustain their professional autonomy. They drew a number of boundaries or distinctions between eugenics and their own field, describing eugenics as politically distorted "bad science, " as being technically unfeasible, a feature of totalitarian regimes, the abuse of neutral knowledge, and as the manipulation of the population's gene pool as opposed to diagnosing and treating individuals with genetic conditions. Their more sophisticated defense strategies invoked the importance of individual choice and the relationship between nature and nurture. The article highlights the ambiguities and difficulties in professionals' use of this rhetoric, drawing on historical and sociological analyses of eugenics, genetics, and medical science and technology more broadly.