Comprehensive Versus Targeted Genetic Testing in Children with Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a genetic disease of the sarcomere that can be found in both children and adults and is associated with many causative mutations. In children who are not the index case of HCM in their families, current recommendations call only for targeted genetic testing for familial mutations. However, clinical experience suggests that de novo mutations are possible, as are mutations inherited from apparently an unaffected parent. A chart review was conducted of all patients who received HCM genetic testing at Johns Hopkins from 2004 to 2013. In total, 239 patient charts were analyzed for personal and familial genetic findings. Eighty-one patients with sarcomere gene mutations were identified, of which 66 had a clinical diagnosis of HCM. Importantly, eight patients had >1 pathogenic or likely pathogenic mutation, including six patients who were diagnosed with HCM as children (18 or younger). In this analysis, when a sarcomere mutation is identified in a family, the likelihood of a child with HCM having >1 mutation is 25 % (6/24), compared to 4.8 % (2/42) for adults. The large number of children with multiple mutations suggests that broad panel rather than targeted genetic testing should be considered in HCM presenting during childhood even if the child is not the index case.

Controlled release delivery of penciclovir via a silicone (MED-4750) polymer: kinetics of drug delivery and efficacy in preventing primary feline herpesvirus infection in culture.

BACKGROUND: Herpesviruses are ubiquitous pathogens that infect and cause recurrent disease in multiple animal species. Feline herpesvirus-1 (FHV-1), a member of the alphaherpesvirus family, causes respiratory illness and conjunctivitis, and approximately 80% of domestic cats are latently infected. Oral administration of famciclovir or topical application of cidofovir has been shown in masked, placebo-controlled prospective trials to reduce clinical signs and viral shedding in experimentally inoculated cats. However, to the authors' knowledge, other drugs have not been similarly assessed or were not safe or effective. Likewise, to our knowledge, no drugs have been assessed in a placebo-controlled manner in cats with recrudescent herpetic disease. Controlled-release devices would permit long-term administration of these drugs and enhance compliance. METHODS: We therefore engineered implantable cylindrical devices made from silicone (MED-4750) impregnated with penciclovir, for long-term, steady-state delivery of this drug. RESULTS: Our data show that these devices release penciclovir with a burst of drug delivery until the tenth day of release, then at an average rate of 5.063 ± 1.704 µg per day through the next 50 days with near zero-order kinetics (in comparison to MED-4750-acyclovir devices, which show the same burst kinetics and average 2.236 ± 0.625 µg/day thereafter). Furthermore, these devices suppress primary infection of FHV-1 in a cell culture system. CONCLUSIONS: The clinical deployment of these silicone-penciclovir devices may allow long-term treatment of FHV-1 infection with a single intervention that could last the life of the host cat.

Novel and highly lethal NKX2.5 missense mutation in a family with sudden death and ventricular arrhythmia.

To date, several disease-related mutations in NKX2-5, a cardiac-specific homeobox gene, have been documented in patients with a variety of congenital heart diseases (CHDs). The most commonly reported phenotypes are secundum atrial septal defect (ASD) and atrioventricular conduction disease (AVCD). Reports of sudden cardiac death (SCD) have been attributed to progressive conduction disease preventable with pacemaker therapy. A retrospective chart review of individuals from three generations of a family with a novel NKX2-5 mutation associated with CHD, ventricular arrhythmias, and SCD despite pacemaker therapy was conducted. The review documented NKX2-5 Gln181His missense mutation in 11 phenotypically affected members of a single family with a strong family history of SCD, CHD, and AVCD. Before genotyping, four family members died suddenly, two despite pacemaker therapy. The ages at SCD were respectively 23, 29, 44, and 45 years. Observed phenotypic characteristics of genotype-positive patients included ASD, ventricular septal defect, aortic coarctation, tricuspid atresia, supraventricular tachycardia, progressive AVCD, and ventricular tachycardia documented on implantable cardiac defibrillator (ICD) recording. The age at presentation ranged from 5 months to 44 years, and AVCD was seen as early as infancy. Four phenotypically unaffected family members tested negative for the mutation. The findings of this review strongly suggest a new association of this NKX2-5 mutation with SCD from ventricular arrhythmia. This observation has significant implications for the choice of therapy for affected individuals, specifically the use of ICDs, and broadens the observed phenotypic spectrum of NKX2-5 mutations.

Genetic testing improves identification of transthyretin amyloid (ATTR) subtype in cardiac amyloidosis.

Amyloidosis is a group of conditions characterized by the accumulation of amyloid deposits in various tissues. Among these disorders, ATTR amyloidosis occurs either with or without a TTR pathogenic variant. Treatment for amyloidosis depends on the subtype, which is often identified through a tissue biopsy followed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Genetic testing may be done to confirm these results for patients with ATTR amyloidosis; however, the necessity of genetic testing after LC-MS/MS has not been evaluated. A retrospective review identified 153 patients diagnosed with biopsy-proven ATTR amyloidosis, and 56 of these patients underwent both genetic testing and LC-MS/MS. LC-MS/MS and proteomics correctly reported the mutant peptide and heterozygosity in 47/56 (84%) cases. It failed to identify two individuals who were homozygous for the ATTRV122I mutation and failed to detect the following mutations in six other individuals: ATTRA19D, ATTRF44L, ATTRT60A, ATTRI68L and ATTRV122I. Therefore, LC-MS/MS is not sufficient to rule out a pathogenic mutation in cases of ATTR amyloid, and genetic testing should be performed in most cases of ATTR amyloidosis. Correct recognition of hereditary ATTR amyloidosis is important for estimating prognosis, proper familial counselling and guiding use of therapies, such as liver transplantation.

Who Pays? Coverage Challenges for Cardiovascular Genetic Testing in U.S. Patients.

Inherited cardiovascular (CV) conditions are common, and comprehensive care of affected families often involves genetic testing. When the clinical presentations of these conditions overlap, genetic testing may clarify diagnoses, etiologies, and treatments in symptomatic individuals and facilitate the identification of asymptomatic, at-risk relatives, allowing for often life-saving preventative care. Although some professional society guidelines on inherited cardiac conditions include genetic testing recommendations, they quickly become outdated owing to the rapid expansion and use of such testing. Currently, these guidelines primarily discuss the benefits of targeted genetic testing for identifying at-risk relatives. Although most insurance policies acknowledge the benefit and the necessity of this testing, many exclude coverage for testing altogether or are vague about coverage for testing in probands, which is imperative if clinicians are to have the best chance of accurately identifying pathogenic variant(s) in a family. In response to uncertainties about coverage, many commercial CV genetic testing laboratories have shouldered the burden of working directly with commercial payers and protecting patients/institutions from out-of-pocket costs. As a result, many clinicians are unaware that payer coverage policies may not match professional recommendations for CV genetic testing. This conundrum has left patients, clinicians, payers, and laboratories at an impasse when determining the best path forward for meaningful and sustainable testing. Herein, we discuss the need for all involved parties to recognize their common goals in this process, which should motivate collaboration in changing existing frameworks and creating more sustainable access to genetic information for families with inherited CV conditions.

Silicone-acyclovir controlled release devices suppress primary herpes simplex virus-2 and varicella zoster virus infections in vitro.

Following initial infection, herpesviruses retreat into a permanent latent state with periodic reactivation resulting in an enhanced likelihood of transmission and clinical disease. The nucleoside analogue acyclovir reduces clinical symptoms of the three human alpha herpesviruses, HSV-1, HSV-2, and VZV. Long-term administration of acyclovir (ACV) can reduce the frequency and severity of reactivation, but its low bioavailability and short half-life require a daily drug regimen. Our lab is working to develop a subcutaneous delivery system to provide long-lasting, sustained release of ACV. Previously, we demonstrated that an implantable silicone (MED-4050) device, impregnated with ACV protected against HSV-1 both in vitro and in vivo. Here, we extend our in vitro observations to include protection against both HSV-2 and VZV. We also demonstrate protection against HSV-2 in vitro using MED-4750, a silicone polymer designed for long-term use in humans. When release of ACV from MED-4750 is quantitated on a daily basis, an initial burst of 5 days is observed, followed by a long period of slow release with near-zero-order kinetics, with an average daily release of 1.3923 ± 0.5908 µ g ACV over days 20-60. Development of a slow-release implant has the potential to significantly impact the treatment of human alpha herpesvirus infections.

Genetic evaluation of familial cardiomyopathy.

Hereditary forms of hypertrophic, dilated, restrictive, and right ventricular cardiomyopathies are frequently seen. Patterns of inheritance include autosomal dominant, autosomal recessive, X-linked, and matrilinear. Recognition of the mode of inheritance facilitates proper clinical screening of family members in subsequent generations. Report of successful sequence analysis of the human genome 7 years ago has resulted in widespread translation of genomic information into clinical applications. As technologic advances in high throughput sequence determination continue to evolve, an era of personalized medicine based on genomic data is highly anticipated. Today, clinical genetic testing is available for most monogenic forms of cardiomyopathy and the demand among patients and families is increasing. However, physicians and patients should consider the benefits and limitations of such testing. This review will focus on inherited forms of cardiomyopathy, detailing the currently available genetic tests, as well as benefits, limitations, and possible outcomes of such testing.