WNT4 and Down syndrome: This new syndrome due to WNT4 mutations in XX women and characterized by absence of Müllerian ducts derivatives, hyperandrogenism and kidney optional adysplasia [80,81], is close but different from MRKH syndrome; therefore, it should be referred to as a proper name, such as "WNT4 syndrome" or "WNT4 defects" and be consequently recorded under an appropriate OMIM number.