The International Committee on Taxonomy of Viruses (ICTV) classifies RNA viruses as those that belong to "Group III", "Group IV" or "Group V" of the Baltimore classification system of classifying viruses and does not consider viruses with DNA intermediates in their life cycle as RNA viruses. Viruses with RNA as their genetic material which also include DNA intermediates in their replication cycle are called retroviruses, and comprise "Group VI" of the Baltimore classification. Notable human retroviruses include HIV-1 and HIV-2, the cause of the disease AIDS.