<unk> (MCOPS12) is an ultra-rare and complex neurological disease. It is caused by a single-point missense mutation in the retinoic acid receptor beta (RARB) gene. The most common disease symptoms are microphthalmia, severe (progressive) movement disorders and intellectual disability. Movement disorders may include spasticity, dystonia and chorea. In addition, malformations such as incomplete lung development (pulmonary hypoplasia), defects of the cerebellum (Chiari type I malformation), and a defect/hole in the diaphragm (diaphragmatic hernia) have been observed.
Microphthalmia, syndromic 12 
Platyspondylic lethal skeletal dysplasia, Torrance type
Orofaciodigital syndrome 1
Ring chromosome 14 syndrome
Lenz microphthalmia syndrome
Tricho–rhino–phalangeal syndrome type 2
Triploid syndrome
Smith Martin Dodd syndrome