Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) T-cell immunodeficiency, congenital alopecia, and nail dystrophy ?
    ### Response:
    T-cell immunodeficiency, congenital alopecia, and nail dystrophy is a type of severe combined immunodeficiency (SCID), which is a group of disorders characterized by an almost total lack of immune protection from foreign invaders such as bacteria and viruses.
    