Specifically, it causes urethritis in both men and women, and also cervicitis and pelvic inflammation in women. It presents clinically similar symptoms to that of Chlamydia trachomatis infection and has shown higher incidence rates, compared to both Chlamydia trachomatis and Neisseria gonorrhoeae infections in some populations. Its complete genome sequence was published in 1995 (size 0.58 Mbp, with 475 genes). It was regarded as a cellular unit with the smallest genome size (in Mbp) until 2003 when a new species of Archaea, namely Nanoarchaeum equitans, was sequenced (0.49 Mbp, with 540 genes). However, Mgen still has the smallest genome of any known (naturally occurring) self-replicating organism and thus is often the organism of choice in minimal genome research.
