Rheumatic heart disease is not hereditary and it is not a genetic disease. Rheumatic heart disease is a hypersensitivity disease caused by an infection, especially following a streptococcal infection. This type of infection leads to the body producing antibodies. In some individuals, these antibodies combine with antigens, causing inflammation of the collagen tissue and affecting the heart. This results in inflammatory lesions on the heart valves, causing the valves to become narrowed or fail to close completely, leading to pathological changes known as rheumatic heart disease.