SON and Global developmental delay: Zhu–Tokita–Takenouchi–Kim syndrome is a multisystem disorder resulting from haploinsufficiency in the SON gene, which is characterized by developmental delay/intellectual disability, seizures, facial dysmorphism, short stature, and congenital malformations, primarily in the central nervous system, along with ophthalmic, dental, pulmonary, cardiologic, renal, gastrointestinal, and musculoskeletal anomalies.