This is supported by the recent report of a male with abnormalities similar to CFNS, including a very wide midface and pronounced hypertelorism, in whom mosaicism for an additional ring X chromosome (composed of a 24-Mb fragment containing the regions Xp11.3 to Xq13.1, including EFNB1) was present in 45% of amniocytes and blood leukocytes [Baker et al., 2010]. Here, EFNB1 is linked to Craniofrontonasal dysplasia.