| A form of pontocerebellar hypoplasia with characteristics of infantile onset of severe global developmental delay with absent speech, hypotonia, feeding problems, dysmorphic craniofacial features, and development of pontocerebellar hypoplasia on brain imaging later in childhood. Other structural abnormalities of the brain, which may already be apparent at an earlier stage, include small hippocampus, thin corpus callosum, periventricular white matter abnormalities, and Dandy-Walker malformation. Seizures, nystagmus, and cortical visual impairment have been reported in some cases. |