<unk>  is a rare brain disorder of malformation of the cerebellum that may be detected on ultrasound of the fetus. The vermis is either absent or partially formed. There is dorsal fusion of the cerebellar hemispheres, fusion of the dentate nuclei, and fusion of the middle cerebellar peduncles. The degree of severity of this disorder is associated with the degree of maldevelopment of the cerebellar vermis. Aqueductal stenosis commonly exists with the disorder, as does its often resulting hydrocephalus. In some cases additional abnormalities may be present, such as ventriculomegaly (enlarged ventricles), and supratentorial abnormalities.
Rhombencephalosynapsis
Germinal matrix hemorrhage
Tooth fusion
Basilar invagination
Monoxenous development
Binaural fusion
Microlissencephaly
Developmental regression