Desmoplakin Cardiomyopathy, a Fibrotic and Inflammatory Form of Cardiomyopathy Distinct From Typical Dilated or Arrhythmogenic Right Ventricular Cardiomyopathy.

BACKGROUND: Mutations in desmoplakin (DSP), the primary force transducer between cardiac desmosomes and intermediate filaments, cause an arrhythmogenic form of cardiomyopathy that has been variably associated with arrhythmogenic right ventricular cardiomyopathy. Clinical correlates of DSP cardiomyopathy have been limited to small case series. METHODS: Clinical and genetic data were collected on 107 patients with pathogenic DSP mutations and 81 patients with pathogenic plakophilin 2 (PKP2) mutations as a comparison cohort. A composite outcome of severe ventricular arrhythmia was assessed. RESULTS: DSP and PKP2 cohorts included similar proportions of probands (41% versus 42%) and patients with truncating mutations (98% versus 100%). Left ventricular (LV) predominant cardiomyopathy was exclusively present among patients with DSP (55% versus 0% for PKP2, P<0.001), whereas right ventricular cardiomyopathy was present in only 14% of patients with DSP versus 40% for PKP2 (P<0.001). Arrhythmogenic right ventricular cardiomyopathy diagnostic criteria had poor sensitivity for DSP cardiomyopathy. LV late gadolinium enhancement was present in a primarily subepicardial distribution in 40% of patients with DSP (23/57 with magnetic resonance images). LV late gadolinium enhancement occurred with normal LV systolic function in 35% (8/23) of patients with DSP. Episodes of acute myocardial injury (chest pain with troponin elevation and normal coronary angiography) occurred in 15% of patients with DSP and were strongly associated with LV late gadolinium enhancement (90%), even in cases of acute myocardial injury with normal ventricular function (4/5, 80% with late gadolinium enhancement). In 4 DSP cases with 18F-fluorodeoxyglucose positron emission tomography scans, acute LV myocardial injury was associated with myocardial inflammation misdiagnosed initially as cardiac sarcoidosis or myocarditis. Left ventricle ejection fraction <55% was strongly associated with severe ventricular arrhythmias for DSP cases (P<0.001, sensitivity 85%, specificity 53%). Right ventricular ejection fraction <45% was associated with severe arrhythmias for PKP2 cases (P<0.001) but was poorly associated for DSP cases (P=0.8). Frequent premature ventricular contractions were common among patients with severe arrhythmias for both DSP (80%) and PKP2 (91%) groups (P=non-significant). CONCLUSIONS: DSP cardiomyopathy is a distinct form of arrhythmogenic cardiomyopathy characterized by episodic myocardial injury, left ventricular fibrosis that precedes systolic dysfunction, and a high incidence of ventricular arrhythmias. A genotype-specific approach for diagnosis and risk stratification should be used.

A survey of aortic disease biorepository participants' preferences for return of research genetic results.

There is ongoing debate on whether and what research genetic results to return to study participants. To date, no study in this area has focused on aortopathy populations despite known genes that are clinically actionable. Participants (n = 225, 79% male, mean age = 61 years) with an aortopathy were surveyed to assess preferences for receiving research genetic results. Participants were 'very' or 'extremely likely' to want results for pathogenic variants in aortopathy genes with implications for family members (81%) or that would change medical management (76%). Similarly, participants were 'very' or 'extremely likely' to want actionable secondary findings related to cancer (75%) or other cardiac diseases (70%). Significantly lower interest was observed for non-actionable findings-pathogenic variants in aortopathy genes that would not change medical management (51%) and variants of uncertain significance (38%) (p < .0001). Higher health and genomic literacy were positively associated with interest in actionable findings. Most participants (>63%) were accepting of any means of return; however, a substantial minority (18%-38%) deemed certain technological means unacceptable (e.g., patient portal). Over 90% of participants reported that a range of health professionals, including cardiovascular specialists, genetics specialists, and primary care providers, were acceptable to return results. Participants with aortopathies are highly interested in research genetic results perceived to be medically actionable for themselves or family members. Participants are accepting of a variety of means for returning results. Findings suggest that research participants should be asked what results are preferred at time of informed consent and that genetic counseling may clarify implications of results that are not personally medically actionable.

Genetic testing impacts the utility of prospective familial screening in hypertrophic cardiomyopathy through identification of a nonfamilial subgroup.

PurposeHypertrophic cardiomyopathy (HCM) is considered a hereditary autosomal dominant condition, but genetic testing is positive in only half of patients. In patients with negative genetic tests, the inheritance pattern and utility of family screening are unclear.MethodsSubjects with HCM were prospectively enrolled in a registry. A survey at a median follow-up of 4 years determined the yield of family screening.ResultsThe outcome of cardiac screening on 267 family members was reported by 120 survey respondents. Subjects with positive genetic test or family history (n=74, 62%) reported an HCM diagnosis in 34 of 203 first-degree relatives who were screened (17%). Affected family members were diagnosed at a mean age of 30-39 years, and 22 of 34 experienced HCM-related adverse events (65%). Gene test-negative subjects with no prior family history of HCM (n=46, 38%) reported an HCM diagnosis in only 2 of 64 first-degree relatives who were screened (3%, p<0.001). These two individuals were diagnosed at age >40 years without HCM-related adverse events.ConclusionHypertrophic cardiomyopathy is a heterogeneous disorder, only half of which tracks with a Mendelian inheritance pattern. Negative genetic testing and family history indicates a more complex genetic basis corresponding to low risk for family members.

At the Heart of the Pregnancy: What Prenatal and Cardiovascular Genetic Counselors Need to Know about Maternal Heart Disease.

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.

Family communication in a population at risk for hypertrophic cardiomyopathy.

Encouraging family communication is an integral component of genetic counseling; therefore, we sought to identify factors impacting communication to family members at risk for Hypertrophic Cardiomyopathy (HCM). Participants (N = 383) completed an online survey assessing: 1) demographics (gender, genetic test results, HCM family history, and disease severity); 2) illness representations; 3) family functioning and cohesiveness; 4) coping styles; 5) comprehension of HCM autosomal dominant inheritance; and 6) communication of HCM risk information to at-risk relatives. Participants were a national sample of individuals with HCM, recruited through the Hypertrophic Cardiomyopathy Association. Data from 183 participants were analyzed using a logistic regression analysis, with family communication as a dichotomous dependent variable. We found that female gender and higher comprehension of autosomal dominant inheritance were significant predictors of participants' communication of HCM risk information to all their siblings and children. Our results suggest that utilizing interventions that promote patient comprehension (e.g., a teaching-focused model of genetic counseling) are important and may positively impact family communication within families with HCM.

A time study of cancer genetic counselors using a genetic counselor-only patient care model versus a traditional combined genetic counselor plus medical geneticist care model.

Analyses of time-based effort have determined that clinical genetic services are labor-intensive, although these data derive primarily from studying geneticists' efforts in the pediatric model. No studies have investigated the time and patient care activities of cancer genetic counselors (GCs) in traditional clinics with a medical geneticist (GC/MD) compared with genetic counselor-only (GCO) appointments. In this study, 6 GCs prospectively tracked time spent in patient care activities in both clinical settings. The authors found that overall, GCs' time spent per patient was lower for GCO versus GC/MD visits. No differences were seen in time spent on results disclosure, but differences were noted in case preparation, face-to-face, and follow-up times. Furthermore, no differences were seen in number of case preparation activities or topics covered during a session. These data suggest that GCO visits result in better use of GCs' time, without a trade-off in number of patient-related activities.

Low yield of genetic testing for known vascular connective tissue disorders in patients with fibromuscular dysplasia.

Patients with fibromuscular dysplasia (FMD) may have clinical features consistent with Mendelian vascular connective tissue disorders. The yield of genetic testing for these disorders among patients with FMD has not been determined. A total of 216 consecutive patients with FMD were identified. Clinical characteristics were collected and genetic test results reviewed for abnormalities in the following genes: transforming growth factor-ß receptor 1 and 2 (TGFßR1 and TGFßR2), collagen 3A1, fibrillin-1, smooth muscle α-actin 2, and SMAD3. A total of 63 patients (63/216; 29.2%) were referred for genetic counseling with testing performed in 35 (35/63; 55.6%). The percentage of patients with a history of arterial or aortic dissection, history of aortic aneurysm, systemic features of a connective tissue disorder, and a family history of sudden death was significantly larger in the group that underwent genetic testing (62.9% vs 18.2%, p < 0.001; 8.6% vs 1.7%, p = 0.02; 51.4% vs 17.1%, p < 0.001; and 42.9% vs 22.7%, p = 0.04, respectively). Two patients were found to have distinct variants in the TGFßR1 gene (c.611 C>T, p.Thr204lle and c.1285 T>C, p.Tyr429His). The yield of genetic testing for vascular connective tissue disorders was low in a high-risk subset of FMD patients. However, two patients with a similar phenotype had novel and distinct variants in the TGFßR1 gene, a finding which merits further investigation.

Disclosure of clinically actionable genetic variants to thoracic aortic dissection biobank participants.

BACKGROUND: Disclosure of pathogenic variants to thoracic aortic dissection biobank participants was implemented. The impact and costs, including confirmatory genetic testing in a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory, were evaluated. METHODS: We exome sequenced 240 cases with thoracic aortic dissection and 258 controls, then examined 11 aortopathy genes. Pathogenic variants in 6 aortopathy genes (COL3A1, FBN1, LOX, PRKG1, SMAD3, and TGFBR2) were identified in 26 participants, representing 10.8% of the cohort (26/240). A second research sample was used to validate the initial findings. Mailed letters to participants disclosed that a potentially disease causing DNA alteration had been identified (neither the gene nor variant was disclosed). Participants were offered clinical genetic counseling and confirmatory genetic testing in a CLIA laboratory. RESULTS: Excluding 6 participants who were deceased or lost to follow-up, 20 participants received the disclosure letter, 10 of whom proceeded with genetic counseling, confirmatory genetic testing, and enrolled in a survey study. Participants reported satisfaction with the letter (4.2 ± 0.7) and genetic counseling (4.4 ± 0.4; [out of 5, respectively]). The psychosocial impact was characterized by low decisional regret (11.5 ± 11.6) and distress (16.0 ± 4.2, [out of 100, respectively]). The average cost for 26 participants was $400, including validation and sending letters. The average cost for those who received genetic counseling and CLIA laboratory confirmation was $605. CONCLUSIONS: Participants were satisfied with the return of clinically significant biobank genetic results and CLIA laboratory testing; however, the process required significant time and resources. These findings illustrate the trade-offs involved for researchers considering returning research genetic results.

Genetic testing and cascade screening in pediatric long QT syndrome and hypertrophic cardiomyopathy.

BACKGROUND: The efficacy of cascade screening for the inherited heart conditions long QT syndrome (LQTS) and hypertrophic cardiomyopathy (HCM) is incompletely characterized. OBJECTIVE: The purpose of this study was to examine the use of genetic testing and yield of cascade screening across diverse regions in the United States and to evaluate obstacles to screening in multipayer systems. METHODS: An institutional review board-approved 6 United States pediatric center retrospective chart review of LQTS and HCM patients from 2008-2014 was conducted for (1) genetic test completion and results and (2) family cascade screening acceptance, methods, results, and barriers. RESULTS: The families of 315 index patients (mean age 9.0 ± 5.8 years) demonstrated a 75% (254) acceptance of cascade screening. The yield of relative screening was 39% (232/601), an average of 0.91 detected per family. Genetic testing was less utilized in HCM index patients and relatives. Screening participation was greater in families of gene-positive index patients (88%) (P <.001) compared to gene-negative patients (53%). Cascade method utilization: Cardiology-only 45%, combined genetic and cardiology 39%, and genetic only 16%. Screening yield by method: combined 57%, genetic-only 29%, and cardiology-only 20%. Family decisions were the leading barriers to cascade screening (26% lack of followthrough and 26% declined), whereas insurance (6%) was the least cited barrier. CONCLUSION: Family participation in cascade screening is high, but the greatest barriers are family mediated (declined, lack of followthrough). Positive proband genetic testing led to greater participation. Cardiology-only screening was the most utilized method, but combined cardiology and genetic screening had the highest detection.

Care in Specialized Centers and Data Sharing Increase Agreement in Hypertrophic Cardiomyopathy Genetic Test Interpretation.

BACKGROUND: Clinically impactful differences in the interpretation of genetic test results occur between laboratories and clinicians. To improve the classification of variants, a better understanding of why discrepancies occur and how they can be reduced is needed. METHODS AND RESULTS: We examined the frequency, causes, and resolution of discordant variant classifications in the Sarcomeric Human Cardiomyopathy Registry (SHaRe), a consortium of international centers with expertise in the clinical management and genetic architecture of hypertrophic cardiomyopathy. Of the 112 variants present in patients at >1 center, 23 had discordant classifications among centers (20.5%; Fleiss κ, 0.54). Discordance was more than twice as frequent among clinical laboratories in ClinVar, a public archive of variant classifications (315/695 variants; 45.2%; Fleiss κ, 0.30; P<0.001). Discordance in SHaRe most frequently occurred because hypertrophic cardiomyopathy centers had access to different privately held data when making their classifications (75.0%). Centers reassessed their classifications based on a comprehensive and current data summary, leading to reclassifications that reduced the discordance rate from 20.5% to 10.7%. Different interpretations of rarity and co-occurrence with pathogenic variants contributed to residual discordance. CONCLUSIONS: Discordance in variant classification among hypertrophic cardiomyopathy centers is largely attributable to privately held data. Some discrepancies are caused by differences in expert assessment of conflicting data. Discordance was markedly lower among centers specialized in hypertrophic cardiomyopathy than among clinical laboratories, suggesting that optimal genetic test interpretation occurs in the context of clinical care delivered by specialized centers with both clinical and genetics expertise.

No apparent damage in the thyroid of transgenic mice expressing antiapoptotic FLIP.

FLIP is an antiapoptotic protein that has been demonstrated to play an important role in inflammation, cancer, and autoimmune diseases. However, it is not known whether increased expression of FLIP (FLICE inhibitory protein) in thyrocytes would alter the development of the thyroid and/or pathogenesis of thyroiditis. To examine the effects of overexpression of this antiapoptotic molecule on the thyroid, we have developed transgenic mouse lines that specifically express FLIP in thyrocytes. A DNA construct designed with an in-frame coding sequence for the E8 protein, a viral FLIP, was put under the control of the thyroglobulin (Tg) promoter (the Tg-FLIP transgene). In 8 of 12 resultant transgenic mouse lines, FLIP expression in thyrocytes driven by the Tg promoter was documented, and confirmed at RNA and protein levels. These Tg-FLIP transgenic mice were monitored for 1 year. Throughout the entire observation period, the transgenic mice remained alive and healthy without evidence of thyroid dysfunction. Adult mice were able to breed. Histologic examination of thyroids obtained at various time points did not reveal significant differences between transgenic mice and their control littermates. Therefore, transgenic mice with thyrocyte-specific expression of FLIP have normal thyroid development with no significant changes in thyroid cell death or proliferation.

A Case for Inclusion of Genetic Counselors in Cardiac Care.

Recent advances in genetic testing for heritable cardiac diseases have led to an increasing involvement of the genetic counselor in cardiology practice. We present a series of cases collected from a nationwide query of genetics professionals regarding issues related to cost and utilization of genetic testing. Three themes emerged across cases: (1) choosing the most appropriate genetic test, (2) choosing the best person to test, and (3) interpreting results accurately. These cases demonstrate that involvement of a genetic counselor throughout the evaluation, diagnosis, and continuing management of individuals and families with inherited cardiovascular conditions helps to promote the efficient use of healthcare dollars.

Aberrant apoptosis in thyroid epithelial cells from goiter nodules.

The specific pathogenesis of nodular goiter and the role of apoptosis in goitrogenesis are not known. We sought to examine the regulation of the TNF-related apoptosis-inducing ligand (TRAIL) and Fas ligand (FasL)-induced apoptosis pathways in primary thyroid cells from 17 patients with nodular goiter, using 10 normal thyroids as controls. Both goitrous and normal thyroid cells were resistant to recombinant human TRAIL and an agonist anti-Fas antibody under basal conditions. However, all normal thyrocytes could be sensitized by TNFalpha/IL-1beta or interferon gamma/IL-1beta to undergo apoptosis in response to TRAIL or FasL, respectively. In contrast, the majority of goiter-derived cells remained resistant to TRAIL (12 of 17 samples) or FasL (9 of 17 samples) after cytokine pretreatment; 14 of 17 goiter nodules were resistant to at least one death ligand. Goiter size was inversely correlated with the sensitivity to TRAIL-mediated apoptosis. The resistance of goiter cells to TRAIL did not appear to be due to transcriptional regulation or cell surface expression of death and decoy receptors. However, increased proteasome activity was found in a subset of goiter cells resistant to both death ligands, and proteasome inhibitors could sensitize these goiter cells to TRAIL-mediated apoptosis. In conclusion, goiter-derived thyroid cells are resistant to TRAIL and/or Fas-induced apoptosis in vitro, and this may represent a new aspect of aberrant growth regulation in goiter nodules. The increased proteasome activity associated with this resistance suggests that the proteasome may be an important regulator of apoptosis in nodular goiter.

A unique combination of inflammatory cytokines enhances apoptosis of thyroid follicular cells and transforms nondestructive to destructive thyroiditis in experimental autoimmune thyroiditis.

Treatment of cultured primary human thyroid cells with IFN-gamma and TNF-alpha uniquely allows the induction of Fas-mediated apoptosis. To investigate the role of this cytokine combination in vivo, CBA/J mice were immunized with thyroglobulin and then injected with IFN-gamma and TNF-alpha. Compared with control animals, mice treated with IFN-gamma and TNF-alpha showed significantly sustained lymphocytic infiltration in the thyroid, which was associated with the destruction of portions of the follicular architecture at wk 6 after initial immunization. Furthermore, the number of apoptotic thyroid follicular cells was increased only in the thyroids from mice treated with the IFN-gamma and TNF-alpha. We also analyzed the function of the Fas pathway in vivo in cytokine-treated mice by using an agonist anti-Fas Ab injected directly into the thyroid. Minimal apoptosis of thyroid epithelial cells was observed unless the mice were pretreated with IFN-gamma and TNF-alpha. These data demonstrate that this unique combination of inflammatory cytokines facilitates the apoptotic destruction of thyroid follicular cells in experimental autoimmune thyroiditis, in a manner similar to what is observed in Hashimoto's thyroiditis in humans.