HOXA13 and Guttmacher syndrome: Another target of CBX2.2 is HOXA13, a homeobox protein whose variants lead to and hand‐foot‐genital syndrome (also known as hand‐foot‐uterinesyndrome) or the related Guttmacher syndrome, dominantly inherited conditions characterized by Müllerian duct fusion defects of varying degree in females and hypospadias in males (Mortlock & Innis, 1997; Scott et al., 2005) (MIM 140000).