 As the thymus is where T cells develop, congenital problems with the development of the thymus can lead to immunodeficiency, whether because of a problem with the development of the thymus gland, or a problem specific to thymocyte development.Immunodeficiency can be profound.Loss of the thymus at an early age through genetic mutation (as in DiGeorge syndrome, CHARGE syndrome, or a vary rare "nude" thymus causing absence of hair and the thymus) results in severe immunodeficiency and subsequent high susceptibility to infection by viruses, protozoa, and fungi.