MedGen

An autoimmune disease characterized by sudden onset of photopsias and scotomata in patients with no family history of retinitis pigmentosa, followed by visual field and central vision loss. [from MONDO]

Chiari malformation type II (CM2), also known as the Arnold-Chiari malformation, consists of elongation and descent of the inferior cerebellar vermis, cerebellar hemispheres, pons, medulla, and fourth ventricle through the foramen magnum into the spinal canal. CM2 is uniquely associated with myelomeningocele (open spina bifida; see 182940) and is found only in this population (Stevenson, 2004). It is believed to be a disorder of neuroectodermal origin (Schijman, 2004). For a general phenotypic description of the different forms of Chiari malformations, see Chiari malformation type I (CM1; 118420). [from OMIM]