Homozygous and compound heterozygous partial deletions of the GRID2 gene (exons 4 and 2) have been identified to cause nystagmus, hypotonia with developmental delay in gross motor skills, encephalopathy with cerebellar ataxia, oculomotor apraxia, and pyramidal tract involvement [18]. This evidence concerns the gene GRID2 and Oculomotor apraxia.