Beyond the One Gene-One Disease Paradigm: Complex Genetics and Pleiotropy in Inheritable Cardiac Disorders

Area of Science:

• Cardiovascular Genetics
• Molecular Cardiology
• Genetic Epidemiology

Background:

• Inheritable cardiac disorders increase sudden death risk in young individuals.
• Early studies identified single gene variants (Mendelian inheritance) for conditions like hypertrophic cardiomyopathy and long-QT syndrome.
• Recent research reveals most inherited heart conditions have complex genetic bases (oligogenic/polygenic inheritance).

Purpose of the Study:

• To review the dual phenomena of multiple genes converging to cause a single phenotype and single genes causing multiple, unrelated phenotypes.
• To explore the complex genetic architecture of inheritable cardiac disorders.
• To discuss pleiotropic gene effects in cardiovascular diseases.

Main Methods:

• Review of genotype-phenotype studies and genetic research.
• Analysis of data from Mendelian and complex inheritable cardiac disorders.
• Detailed examination of specific genes like SCN5A and PKP2 and their associated conditions.

Main Results:

• Most inheritable cardiac disorders exhibit oligogenic or polygenic inheritance patterns.
• Single genes can influence multiple, seemingly unrelated phenotypes (pleiotropy).
• Studies on long-QT syndrome, Brugada syndrome, and arrhythmogenic cardiomyopathy illustrate these complex genetic principles.

Conclusions:

• Inheritable cardiac disorders often involve intricate genetic interactions, with multiple genes contributing to a single condition.
• Pleiotropy, where one gene affects diverse phenotypes, is a significant factor in cardiovascular genetics.
• Understanding these complex genetic relationships is crucial for diagnosing and managing inheritable heart diseases.