<prompt> Keshan disease is caused by deficiency of:ThiamineZincSeleniumProteins  <response>: Ans. C. Selenium Selenium is a constituent of glutathione peroxidase, an antioxidant in red blood cells and other tissues. Glutathione peroxidase scavenges free Hydro peroxidases generated during fatty acid oxidation, thus protecting the cell from damage due to free radical formation. Severe deficiency is the major cause of Keshan disease, which presents as cardiomyopathy in young children. Skeletal myopathies have also been reported. Mild deficiency is associated with macrocytosis and loss of hair pigment. 