Pan Cardiomyopathy Panel

Cardiomyopathies are disorders of the myocardium that manifest with various structural and functional changes of the heart. The expressivity of cardiomyopathy is highly variable and patients may present symptoms such as shortness of breath, fatigue, dizziness, fluttering, swelling in the ankles and legs, etc. (Maron et al. 2006; McNally et al. 2015). Clinical heterogeneity may be partially attributed to genetic heterogeneity of the cardiomyopathy disorders. The contribution of genetic factors varies by disorder subtypes and age of onset (Ackerman et al. 2011). Cardiomyopathies include a broad range of disorders, including Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Arrhythmogenic Right Ventricular Cardiomyopathy, and Left Ventricular Non-Compaction Cardiomyopathy. Pan cardiomyopathy panel testing could help with differential diagnosis and prognostic stratification for patients with cardiomyopathies (Charron et al. 2010).

Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D) primarily affects the right ventricle. It is characterized by myocardial atrophy, fibrofatty replacement of the ventricular myocardium and inflammatory infiltrates (McNally et al. 2014).

Left Ventricular Noncompaction (LVNC) Cardiomyopathy is believed to be caused by an arrest in cardiac development during embryogenesis, resulting in a spongy, noncompacted appearance. The numerous trabeculations are most pronounced in the left ventricle (Oechslin et al. 2011; Hoedemaekers et al. 2010).

Dilated Cardiomyopathy (DCM) is a heterogeneous disease of the cardiac muscle characterized by dilatation of the left, right, or both ventricles, systolic dysfunction, and diminished myocardial contractility (Hershberger et al. 2013).

Hypertrophic Cardiomyopathy (HCM) is a primary disease of the cardiac muscle characterized by idiopathic hypertrophy of the left ventricle, although hypertrophy of the right ventricle may also occur. HCM is distinguished by extensive clinical variability between individuals, even within the same family (Cirino et al. 2014).

Cardiomyopathy represents a group of genetically heterogeneous disorders with substantial genetic component. Genetic causes could contribute significantly in 60% of hypertrophic cardiomyopathy cases, and 30-50% of Dilated Cardiomyopathy cases (Teekakirikul et al. 2013). The inheritance mode of cardiomyopathy disorders include autosomal dominant (AD), autosomal recessive (AR), and X-linked (XL). The majority of cardiac-related genes are associated with autosomal dominant disorders. The ALMS1, DOLK, FKRP, FKTN, GAA, GATAD1, LAMA2, SCO2, and SGCG are associated with autosomal recessive cardiac-related disorders. The DSC2, DSP, JUP, LMNA, SCN5A, TNNI3, and TTN genes are associated with autosomal dominant and recessive cardiac-related disorders. The FHL1, GLA, LAMP2, DMD, EMD, and TAFAZZIN genes are associated with X-linked recessive cardiac-related disorders, except for LAMP2, which is involved in X-linked dominant cardiac-related disorders (OMIM; Human Gene Mutation Database). See individual gene test descriptions for information on molecular biology of gene products.

The sensitivity of this panel varies based on the type of disease. This test is predicted to detect causative variants in ~60% of Hypertrophic Cardiomyopathy patients (Morita et al. 2008; Hershberger et al. 2009), up to 30% of adults with Left Ventricular Noncompaction (Ichida et al 2001; Vatta et al. 2003; Hermida-Prieto et al. 2004; Klaassen et al. 2008; Hoedemaekers et al. 2010), 30-40% of patients with familial Dilated Cardiomyopathy (Hershberger and Morales 2013), and ~73% of patients with autosomal dominant or sporadic Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (McNally et al. 2014; Bhuiyan et al. 2009).

Gross deletions or duplications have been reported in CAV3, DES, DSP, NKX2-5, PKP2, RYR2 and SCN5A as individual cases (Human Gene Mutation Database).

This test is performed using Next-Gen sequencing with additional Sanger sequencing as necessary.

This panel typically provides 98.5% coverage of all coding exons of the genes plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define coverage as ≥20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).