Abnormal cerebellar foliation in EBF3 mutation.

A 5-month-old patient was first evaluated for a hypotonic hyporeflexic syndrome; over years, the phenotype evolved to involve ataxia, developmental delay, and coarse facies. Brain MRI showed abnormal configuration of cerebellar folia, rearranged in radial shape (figure). Whole exome sequencing analysis revealed the c.512 G>A (p.G171D) de novo mutation in EBF3 . EBF3 gene function is crucial for neuronal migration during corticogenesis.1 Cerebellar foliation is complex: folia sprout from anchoring centers,2 whose distribution and number determine the shape of lobules and fissures; EBF3 mutations may disrupt this process, thus causing the peculiar cerebellar lobule appearance seen here.