Human Genetics of Ventricular Septal Defect.

Ventricular septal defects (VSDs) are recognized as one of the commonest congenital heart diseases (CHD), accounting for up to 40% of all cardiac malformations, and occur as isolated CHDs as well as together with other cardiac and extracardiac congenital malformations in individual patients and families. The genetic etiology of VSD is complex and extraordinarily heterogeneous. Chromosomal abnormalities such as aneuploidy and structural variations as well as rare point mutations in various genes have been reported to be associated with this cardiac defect. This includes both well-defined syndromes with known genetic cause (e.g., DiGeorge syndrome and Holt-Oram syndrome) and so far undefined syndromic forms characterized by unspecific symptoms. Mutations in genes encoding cardiac transcription factors (e.g., NKX2-5 and GATA4) and signaling molecules (e.g., CFC1) have been most frequently found in VSD cases. Moreover, new high-resolution methods such as comparative genomic hybridization enabled the discovery of a high number of different copy number variations, leading to gain or loss of chromosomal regions often containing multiple genes, in patients with VSD. In this chapter, we will describe the broad genetic heterogeneity observed in VSD patients considering recent advances in this field.

Clinical Presentation and Therapy of Cardiomyopathies.

Cardiomyopathies are a group of diseases that primarily affect the heart muscle, leading to mechanical or electrical dysfunction of the heart. They can be categorized into primary and secondary forms. Primary cardiomyopathies can be further classified as congenital, acquired, or mixed. In terms of the heart muscle itself, there are five distinct types of cardiomyopathies: hypertrophic cardiomyopathy, dilated or congestive cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic (right ventricular) dysplasia, and noncompaction cardiomyopathy. While cardiomyopathies primarily affect the heart, they can also have systemic manifestations, impacting other organs and potentially causing progressive debilitation, heart failure, or even death.