**1. Introduction**

Cardiomyopathy, a primary cause of human death, is defined as a disease of the myocardium, which results in insufficient pumping of the heart. It is classified into four major forms; hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), restrictive cardiomyopathy (RMC), and arrhythmogenic right ventricular cardiomyop‐ athy (ARVC) [1]. These are characterized by extensive remodeling of the myocardium initially manifested as hypertrophy, evidenced by an increase in the thickness of the left ventricular wall and interventricular septum due to interstitial fibrosis and enlarged myocyte size. Following hypertrophy the heart muscle reverts to a dilated state, characterized by a profound expansion of the intraventricular volume and a modest increase in ventricular wall thickness [2]. These changes, initially compensatory, eventu‐ ally become maladaptive.

During the past ~20 years, several mutations in genes encoding sarcomeric proteins have been causally linked to cardiomyopathies [1]. Among the long list of affected proteins are three members of the family of giant sarcomeric proteins of striated muscles: titin, nebulette, a member of the nebulin subfamily, and obscurin, each encoded by single genes namely *TTN*, *NEBL*, and *OBSCN*, respectively [3]-[10]. This chapter will briefly describe the molecular structure of these genes, assisting the reader to excellent de‐ tailed reviews when appropriate, and further provide a comprehensive and up-to-date listing of the mutations that have been identified and directly linked to the develop‐ ment of cardiomyopathy.

original work is properly cited.

© 2013 Ackermann and Kontrogianni-Konstantopoulos; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/ licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
