Transthyretin amyloid polyneuropathy in France: A cross-sectional study with 413 patients and real-world tafamidis meglumine use (2009-2019).

OBJECTIVE: We aimed to describe characteristics of patients with ATTR variant polyneuropathy (ATTRv-PN) and ATTRv-mixed and assess the real-world use and safety profile of tafamidis meglumine 20mg. METHODS: Thirty-eight French hospitals were invited. Patient files were reviewed to identify clinical manifestations, diagnostic methods, and treatment compliance. RESULTS: Four hundred and thirteen patients (296 ATTRv-PN, 117 ATTRv-mixed) were analyzed. Patients were predominantly male (68.0%) with a mean age of 57.2±17.2 years. Interval between first symptom(s) and diagnosis was 3.4±4.3 years. First symptoms included sensory complaints (85.9%), dysautonomia (38.5%), motor deficits (26.4%), carpal tunnel syndrome (31.5%), shortness of breath (13.3%), and unexplained weight loss (16.0%). Mini-invasive accessory salivary gland or punch skin and nerve biopsies were most common, with a performance of 78.8-100%. TTR genetic sequencing, performed in all patients, revealed 31 TTR variants. Tafamidis meglumine was initiated in 156/214 (72.9%) ATTRv-PN patients at an early disease stage. Median treatment duration was 6.00 years in ATTRv-PN and 3.42 years in ATTRv-mixed patients. Tafamidis was well tolerated, with 20 adverse events likely related to study drug among the 336 patients. CONCLUSION: In France, ATTRv patients are usually identified early thanks to the national network and the help of diagnosis combining genetic testing and mini-invasive biopsies.

Secondary findings from next generation sequencing: Psychological and ethical issues. Family and patient perspectives.

Access to active search for actionable secondary findings (SF) in diagnostic practice is a major psychological and ethical issue for genomic medicine. In this study, we analyzed the preferences of patients and their families regarding SF and identified the reporting procedures necessary for informed consent. We interviewed parents of patients with undiagnosed rare diseases potentially eligible for exome sequencing and patients affected by the diseases listed in the ACMG recommendations. Four focus groups (FG) were formed: parents of patients with undiagnosed rare diseases (FG1, n = 5); patients with hereditary cancers (FG2, n = 10); patients with hereditary cardiac conditions (FG3, n = 3); and patients with metabolic diseases (FG4, n = 3). Psychologists presented three broad topics for discussion: 1. Favorable or not to SF access, 2. Reporting procedures, 3. Equity of access. Discussions were recorded and analyzed using simplified Grounded Theory. Overall, 8 participants declared being favorable to SF because of the medical benefit (mainly FG1); 11 were unfavorable because of the psychological consequences (mainly FG2, FG3, FG4); 2 were ambivalent. The possibility of looking for SF in minors was debated. The 4 key information-based issues for participants ranked as follows: explanation of SF issues, autonomy of choice, importance of a reflection period, and quality of interactions between patients and professionals. Examining equity of access to SF led to philosophical discussions on quality of life. In conclusion, individual experience and life context (circumstances) were decisive in participants' expectations and fears regarding access to SF. Additional longitudinal studies based on actual SF disclosure announcements are needed to establish future guidelines.

Pregnancy and newborn outcomes in arrhythmogenic right ventricular cardiomyopathy/dysplasia.

INTRODUCTION: The prognosis of pregnancy in patients with Arrhythmogenic Right Ventricular Cardiomyopathy/dysplasia (ARVC/D) is poorly documented. The aim of this study is to assess the cardiac risks during pregnancy and the impact of ARVC/D on fetuses/neonates/children. METHODS: We included all ARVC/D women with a history of pregnancy from the ARVC/D Pitié-Salpêtrière registry. Cardiac and obstetrical events having occurred during pregnancy/delivery/post-partum periods and neonatal data/follow-up were collected. RESULTS: Sixty pregnancies in twenty-three patients were identified between 1968 and 2016. Only two major non-fatal cardiac events (one sustained non-documented tachycardia and one ventricular tachycardia) were recorded during pregnancy in two different mothers (3% of pregnancies, 9% of mothers). None occurred during delivery or in the postpartum period. No mother developed heart failure. Beta-blocker therapy during pregnancy (n=15) was associated with lower birthweight (2730 vs 3400g, p=0.004). Only two preterm deliveries occurred, unrelated to cardiac condition. Caesarean section was performed in 13% of cases. Premature sudden-death occurred in 10% (n=5) of children before 25years-old including two in the first year of life. CONCLUSION: ARVC/D is associated with a low rate of major cardiac events during pregnancy and vaginal delivery appears safe. The risk of sustained ventricular arrhythmia seems poorly predictable and supports the continuation of beta-blockers during pregnancy. Major cardiac events were frequent in childhood, justifying close cardiac monitoring.

Significance of deep T-wave inversions in asymptomatic athletes with normal cardiovascular examinations: practical solutions for managing the diagnostic conundrum.

Preparticipation screening programmes for underlying cardiac pathologies are now commonplace for many international sporting organisations. However, providing medical clearance for an asymptomatic athlete without a family history of sudden cardiac death (SCD) is especially challenging when the athlete demonstrates particularly abnormal repolarisation patterns, highly suggestive of an inherited cardiomyopathy or channelopathy. Deep T-wave inversions of ≥ 2 contiguous anterior or lateral leads (but not aVR, and III) are of major concern for sports cardiologists who advise referring team physicians, as these ECG alterations are a recognised manifestation of hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Subsequently, inverted T-waves may represent the first and only sign of an inherited heart muscle disease, in the absence of any other features and before structural changes in the heart can be detected. However, to date, there remains little evidence that deep T-wave inversions are always pathognomonic of either a cardiomyopathy or an ion channel disorder in an asymptomatic athlete following long-term follow-up. This paper aims to provide a systematic review of the prevalence of T-wave inversion in athletes and examine T-wave inversion and its relationship to structural heart disease, notably HCM and ARVC with a view to identify young athletes at risk of SCD during sport. Finally, the review proposes clinical management pathways (including genetic testing) for asymptomatic athletes demonstrating significant T-wave inversion with structurally normal hearts.

Plakophilin 2A is the dominant isoform in human heart tissue: consequences for the genetic screening of arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart disease in which mutations affecting Plakophilin-2 (PKP2) are the most frequently detected. However, pathogenicity of variants is not always fully determined. PKP2 encodes two isoforms, the longest (PKP2b) includes the alternatively spliced exon 6, which is routinely screened for molecular diagnosis, despite the absence of data on cardiac expression of PKP2 isoforms. OBJECTIVE: To examine the pathogenicity of PKP2 exon 6 mutations by focusing on a missense variant located in this exon. METHODS AND RESULTS: The PKP2 heterozygous p.Arg490Trp variant was identified in two unrelated ARVC probands (absent from 470 controls). In silico analysis suggested that PKP2 exon 6 is an Alu-derived sequence with very low expression level. PKP2a mRNA, which does not include the sequence encoded by exon 6, was the dominant isoform transcribed; at western blot analysis PKP2A was the only clearly detectable isoform in all human heart samples analysed (from six different controls and the proband). Moreover, in the proband's sample, p.Arg490Trp was not associated with aberrant exon 6 splicing or mutant mRNA downregulation. Finally, a heterozygous missense variant (p.Glu2343Lys) in Desmoplakin was identified in this proband and is likely to be the disease-causing mutation. CONCLUSION: PKP2A was shown to be the major isoform expressed in human heart tissue and PKP2B protein was undetectable. The results strongly suggest that p.Arg490Trp and other variants located in PKP2 exon 6 may not be disease causing. Variant splicing also has important consequences for the interpretation of mutation analysis and genetic counselling in ARVC and other hereditary cardiac diseases.

[Genetics of inherited cardiomyopathies]. / Génétique des cardiomyopathies héréditaires.

Hereditary cardiomyopathy is a primitive disorder in which the heart muscle is structurally and functionally abnormal in the absence of any other cause of cardiomyopathy. They are separated into four phenotypic groups, hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy and arrhythmogenic cardiomyopathy of the right ventricle. Hypertrophic cardiomyopathy was the first identified at the molecular level and then the first to benefit of molecular testing. The molecular analyses were then extended the following years to the dilated cardiomyopathy and restrictive cardiomyopathy. The arrhythmogenic right ventricular cardiomyopathy was the latest to be analyzed at the molecular level because the identification of genes involved in that phenotype was published only in 2002 to 2006. The genetics analysis of these diseases has developed over the past decade and, although still complex, is now available in current hospital practice. The objectives of these tests are to confirm a diagnosis difficult to achieve by classic clinical approach and to perform predictive and presymptomatic diagnosis in families when the mutation was identified. This allows for appropriate care of patients at risk, and may respond to a request for prenatal diagnosis in particularly serious forms. These tests are framed in the context of genetic counselling consultation and patients are the subjects of a multidisciplinary care in reference centres.

[A familial form of conduction defects associated with a PRKAG2 gene mutation]. / Une forme familiale de troubles conductifs associés à une mutation du gène PRKAG2.

Conduction defects are usually secondary to elective aging of the conduction pathways. However, some familial and genetic forms are now being described. Here we report a particular electrocardiographic pattern in four members of the same family over three generations, naturally leading to the suspicion of a hereditary origin. The ECG appearance is very specific and includes conduction defects (RBBB and occasionally left anterior hemiblock), short PR interval, pseudo appearance of atrial hypertrophy, and occasionally sinus dysfunction or supraventricular extrasystole. Gene analysis identified a R302Q mutation of the gamma2 subunit producing AMP protein kinase, coded by the gene PRKAG2. This is a wrong sense mutation present in the heterozygous state in each of those displaying the ECG anomalies, and is transmitted in an autosomal dominant fashion. The clinical picture here appears to constitute a clinical entity distinct from those previously described as being associated with mutations of the PRKAG2 gene, without any left ventricular hypertrophy or Wolff-Parkinson-White syndrome.

[Diagnostic value of a two-dimensional echocardiographic score for left ventricular hypertrophy validated by the Imatron CT scan in familial hypertrophic cardiomyopathy]. / Valeur diagnostique d'un score echocardiographique bidimensionnel d'hypertrophie du ventricule gauche validé par scanner Imatron dans la cardiomyopathie hypertrophique familiale.

The aim of this study was to validate a two-dimensional echocardiographic score for left ventricular hypertrophy in familial hypertrophic cardiomyopathy (HCM) by fast CT scan and to study the diagnostic value by an indexed threshold value in affected and genotyped families in comparison with the classical diagnostic method of maximal wall thickness (E max). The study was performed successively in two patient groups with HCM. The echo/CT scan population comprised 26 patients. They underwent echocardiography and Imatron CT scanning. The E max and 2D echo score (sum of the thickness of 4 segments) were measured by echocardiography and compared to the left ventricular mass obtained by the CT method. The 2D echo score was closely correlated to the CT left ventricular mass (r = 0.85) with a higher correlation coefficient than the E max (r = 0.78). The echo/generic population comprised 109 genotyped adults with an identified mutation. The E max and 2D echo score were measured. The genotype was the reference for diagnosis. A theoretical value of the 2D echo score was determined in healthy individuals by a multiple linear regression model of ages, sex and body surface area. A threshold value for abnormality was established after analysis of the ROC. The sensitivity and specificity were 63% and 100% respectively for E max and 73% and 96% respectively for the indexed 2D echo score. The improvement in sensitivity was marked in young adults (< 50 years) with 69% for the indexed 2D echo score versus 54% for E max, p < 0.04. The authors conclude that the indexed 2D score has been validated as an index of hypertrophy by the Imatron CT and has a better diagnostic value than E max, especially in young adults. This echocardiographic criterion could be proposed as an alternative diagnostic sign for screening families.

Danon's disease as a cause of hypertrophic cardiomyopathy: a systematic survey.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease caused by mutations in sarcomeric genes. However, extensive genetic screening failed to identify a mutation in about a third of cases. One possible explanation is that other diseases, caused by other genes, may mimic HCM. OBJECTIVE: To investigate the possible involvement of Danon's disease, an X linked lysosomal disease, in a large population of patients with HCM. METHODS: A population of 197 index cases was considered; 124 were subsequently excluded because of a mutation in sarcomeric genes and 23 because of autosomal dominant inheritance. Fifty index cases were therefore included in molecular analysis (direct sequencing) of the lysosome associated membrane protein 2 (LAMP2) gene responsible for Danon's disease. RESULTS: Two new mutations leading to premature stop codons were identified in patients who evolved towards severe heart failure (< 25 years old): 657C>T and 173_179del. The prevalence was therefore 1% of the total population (two of 197) or 4% of enrolled index cases (two of 50). Interestingly, Danon's disease was responsible for half of the cases (two of four) with HCM and clinical skeletal myopathy but was not involved in isolated HCM (none of 41). CONCLUSIONS: Danon's disease may be involved in patients with previously diagnosed as HCM. A diagnosis strategy is proposed. To distinguish HCM from Danon's disease is important because the clinical evolution, prognosis, mode of inheritance, and therefore genetic counselling are very different.

[Genetic counseling in cardiology]. / Le conseil génétique en cardiologie.

Progress in the recognition of genetic factors implicated in cardiovascular diseases is now such that it poses the question of how to integrate these data into a clinical perspective. To be able to give the most relevant information to the patient and his family, and to use this information to optimise the medical management have become new objectives. This can only be achieved with the close collaboration between cardiologist and the genticist, who knows the legislative framework which governs the performance of genetic tests. During the genetic counselling consultation, and after time for compiling information on the disease and the family, the geneticist gives the most suitable information on the genetic nature of the disease. Depending on the illness, cardiological investigation for the relatives could be advocated. The performance of a molecular test is then discussed, as a function of its feasibility, relevance and the wishes of the patient. The complexity of the medical and psychological stakes varies according to the situation (presymptomatic diagnosis, prenatal diagnosis, diagnostic test, prognostic test) and the condition. In all cases, strict rules perfectly laid down by legislation must be respected, in such a way as to protect the patient from possible unfavourable repercussions and to assure him of better medical management and a greater well-being.

[Genetic features of atrial fibrillation]. / Aspects génétiques de la fibrillation auriculaire.

Etiology of atrial fibrillation remains largely unknown. Molecular genetics is a powerful tool that may help to identify underlying mechanisms of the arrhythmia. As a matter of fact, a major step forward was the recent identification of the KCNQ1 gene coding a subunit of a potassium channel in IKS current as responsible for idiopathic atrial fibrillation in a familial autosomal dominant form. The KCNQ1 gain-of-function mutation may induce a shortening in action potential and in effective refractory periods leading to the initiation and persistence of atrial fibrillation. In the multifactorial forms of the disease, by far the most frequent, susceptibility genes and modifier genes are also currently being identified. This better understanding of the disease leads to new perspectives, particularly for therapeutists, and would enable them to work with more interest.

Expanding the phenotype of LMNA mutations in dilated cardiomyopathy and functional consequences of these mutations.

AIMS: Mutations in the lamin A/C gene (LMNA) have been reported to be involved in dilated cardiomyopathy (DCM) associated with conduction system disease and/or skeletal myopathy. The aim of this study was to perform a mutational analysis of LMNA in a large white population of patients affected by dilated cardiomyopathy with or without associated symptoms. METHODS: We performed screening of the coding sequence of LMNA on DNA samples from 66 index cases, and carried out cell transfection experiments to examine the functional consequences of the mutations identified. RESULTS: A new missense (E161K) mutation was identified in a family with early atrial fibrillation and a previously described (R377H) mutation in another family with a quadriceps myopathy associated with DCM. A new mutation (28insA) leading to a premature stop codon was identified in a family affected by DCM with conduction defects. No mutation in LMNA was found in cases with isolated dilated cardiomyopathy. Functional analyses have identified potential physiopathological mechanisms involving identified mutations, such as haploinsufficiency (28insA) or intermediate filament disorganisation (E161K, R377H). CONCLUSION: For the first time, a specific phenotype characterised by early atrial fibrillation is associated with LMNA mutation. Conversely, mutations in LMNA appear as a rare cause of isolated dilated cardiomyopathy. The variable phenotypes observed in LMNA-DCM might be explained by the variability of functional consequences of LMNA mutations.

Accuracy of European diagnostic criteria for familial hypertrophic cardiomyopathy in a genotyped population.

BACKGROUND: Since the sensitivity of conventional diagnostic criteria for familial hypertrophic cardiomyopathy (HCM) is low, new diagnostic criteria were proposed by a European collaboration. However, their diagnostic value remains unknown. The aim of the study was to evaluate the accuracy of these new criteria, using the genetic status as the criterion of reference. METHODS: We studied 109 genotyped adults (54 genetically affected, 55 unaffected) from 7 families (mutations in 3 genes). Major European echographic criteria were a maximal wall thickness >or=13 mm or >or=15 mm according to the segment involved, or the presence of SAM. Major European ECG criteria were abnormal Q waves, left ventricular hypertrophy, or marked ST-T changes. Combined major/minor European criteria were also evaluated. RESULTS: Sensitivity and specificity of major European criteria (72 and 92%, respectively) were similar to those of major conventional criteria (70 and 94%) and were not improved by combined major/minor European criteria (72 and 90%). When all the minor European criteria were considered, sensitivity increased to 87% but specificity dramatically decreased to 51%. However, one of these minor ECG criteria, deep S V2, was of interest and when added to major European criteria, sensitivity increased to 76% and specificity remained good (90%). CONCLUSIONS: The diagnostic value of new European criteria for HCM was evaluated for the first time. We found that it was not different from that of conventional criteria, with a good specificity but a low sensitivity. Additional criteria should be studied to improve the early identification of HCM.

Genetic testing and genetic counselling in hypertrophic cardiomyopathy: the French experience.

AIMS: A major breakthrough in the molecular genetics of hypertrophic cardiomyopathy (HCM) has made genetic testing now available in clinical practice, raising new questions about its implications, potential benefits, and the organisation of the procedure. The aim of this work was (1) to discuss the different questions related to genetic testing in HCM, and propose guidelines for the different situations, (2) to report our preliminary experience with a specific procedure. METHODS AND RESULTS: The main questions asked by patients and relatives concern presymptomatic diagnosis and prenatal counselling/diagnosis, while clinicians sometimes discuss diagnostic and prognostic testing. To take into account the complex medical and psychological implications of this new approach, we developed a specific, multidisciplinary, and multiple step procedure, including a cardiologist, a geneticist, and a psychologist. Seventy subjects were examined, including (1) 29 adults for presymptomatic diagnosis (of whom 10 left the procedure after the first visit and 19 continued, among whom six had a mutation and two experienced negative psychological impact, observed during follow up), (2) nine couples of parents for presymptomatic diagnosis in their children (the procedure was stopped after the first visit in eight and continued in one), (3) 22 couples for prenatal counselling (no prenatal genetic testing was asked for after the first visit), and (4) 10 subjects for diagnostic testing. We decided to perform no prognostic testing. CONCLUSION: Our preliminary experience confirms the complexity of the situation and suggests the necessity for a specific procedure to ensure good practice in genetic testing of HCM.