Role of genetic testing in cardiomyopathies: Α primer for cardiologists

Table 1 Terminology of commonly used genetics vocabulary

Term	Definition
Allele	One of several alternative versions of a particular gene
Heterozygote	An individual who has different alleles at a particular gene locus on homologous chromosomes (carrier of a single copy of the mutation)
Mutation	Any alteration in the inherited nucleic acid sequence of the genotype of an organism; a mutation considered in the context of a genetic disease usually refers to an alteration that causes a Mendelian disease
Penetrance	Proportion of individuals carrying a mutation who also express a cardiomyopathy phenotype
Genome sequencing	Sequencing of entire genome (coding and non-coding regions)
Exome sequencing	Sequencing of the coding regions (exons)
Proband or index case	Index case in the family, usually the one with the most severe phonotype
Variant	A change in the DNA sequence which may or may not be disease-causing
Pathogenicity	Process of determining whether a variant is causative or not