Christianson syndrome (CS) is caused by mutations in SLC9A6 and is characterized 
by severe intellectual disability, absent speech, microcephaly, ataxia, 
seizures, and behavioral abnormalities. The clinical phenotypes of CS and 
Angelman syndrome (AS) are similar. Differentiation between CS and AS is 
important in terms of genetic counseling. We report on two children with CS and 
confirmed mutations in SLC9A6 focusing on neuroimaging findings and review the 
available literature. Cerebellar atrophy (CA) occurs in approximately 60% of the 
patients with CS and develops after the age of 12 months. Hyperintense signal of 
the cerebellar cortex (CbC) is less common, and may be diffuse, patchy, or 
involve only the inferior part of the cerebellum and is best seen on coronal 
fluid attenuation inversion recovery images. CA and CbC-hyperintensity are not 
neuroimaging features of AS. In a child with the phenotype of AS, CA and/or 
CbC-hyperintensity are rather specific for CS and should prioritize sequencing 
of SLC9A6.