Determinants of incomplete penetrance and variable expressivity in heritable cardiac arrhythmia syndromes

Incomplete Penetrance and Variable Expressivity: Hallmarks in Channelopathies Associated with Sudden Cardiac Death

Sudden cardiac death is defined as an unexpected decease of cardiac origin. In individuals under 35 years old, most of these deaths are due to familial arrhythmogenic syndromes of genetic origin, also known as channelopathies. These familial cardiac syndromes commonly follow an autosomal dominant pattern of inheritance. Diagnosis, however, can be difficult, mainly due to incomplete penetrance a...

Inherited Cardiac Arrhythmia Syndromes

Lethal cardiac arrhythmias in individuals with structurally normal heart are often caused by variants in genes that encode cardiac ion channel and -subunits (102). Common inherited arrhythmia syndromes include the congenital long QT syndrome (LQTS), Brugada syndrome (BrS), short QT syndrome (SQT), and catecholaminergic polymorphic ventricular tachycardia (CPVT) (76). Moreover, inherited mutatio...

The variable expressivity and incomplete penetrance of the twist-null heterozygous mouse phenotype resemble those of human Saethre-Chotzen syndrome.

Most targeted gene mutations are recessive and analyses of gene function often focus on homozygous mutant phenotypes. Here we describe parts of the expression pattern of M-twist in the head of developing wild-type mice and present our analysis of the phenotype of heterozygous twist- null animals at around birth and in adults. A number of twist -null heterozygous mice present skull and limb defe...

Cardiac sodium channel and inherited arrhythmia syndromes.

Reduced penetrance, variable expressivity, and genetic heterogeneity of familial atrial septal defects.

BACKGROUND Secundum atrial septal defect (ASD) is a common congenital heart malformation that occurs as an isolated anomaly in 10% of individuals with congenital heart disease. Although some embryological pathways have been elucidated, the molecular etiologies of ASD are not fully understood. Most cases of ASD are isolated, but some individuals with ASD have a family history of this defect or o...