Neurodevelopmental syndromes have been associated not only with KAT6A but also with KAT6B and BRPF1. KAT6B mutations are associated with Say-Barber-Biesecker-Young-Simpson syndrome (SBBYSS, MIM # 603736) and Genitopatellar syndrome (MIM # 606170), while BRPF1 mutations associate with IDDDFP (Intellectual developmental disorder with dysmorphic facies and ptosis, MIM # 617333). Here, KAT6B is linked to ptosis.