This approach does not require prior knowledge about the function of the disease gene. Identification of disease genes leads to an understanding of the biological causes of disease. Either the gene or its protein product can serve as the basis of a diagnostic test or a potential target for therapy. However, there are mutations that have the opposite effect and appear to protect the heart from disease. Hypertrophied hearts that are characteristic of hypertrophic cardiomyopathy contain larger rather than more cells.
Mutations affecting heart muscle contractile proteins cause hypertrophic disease.
The multiplicity of genes and mutations involved results in the variety of signs and symptoms of disease. The expression of genetic defects in an individual is typically influenced by other genes, lifestyle, and environment. Mice that have been genetically engineered with heart disease mutations provide models for exploring how gender, exercise, and environment shape heart disease. Although the primary causes of hypertension remain unknown in the vast majority of subjects, mutations in certain genes appear to be involved in specific types of hypertension. Molecular genetic approaches have led to the identification of single genes on specific chromosomes that, when mutated, can lead to elevated blood pressure.