Periodic alternating gaze deviation with dissociated secondary face turn

Periodic alternating gaze (PAG) deviation and secondary face turn occurred in a 4-year-old boy with an Arnold-Chiari (Chiari type 2) malformation and hydrocephalus. The child also had a periodic alternating esotropia. Reports of only three other similar cases could be found. To our knowledge, this is the youngest patient described in the literature and the first time PAG deviation and esotropia have been associated with the Arnold-Chiari malformation.