Fig. 1

a, Axial, b, Coronal, and c, Sagittal T2-weighted images of a 17-year-old male with seizures and cerebellar hypoplasia of unknown origin show reduced volume, but near normal structure of the cerebellum. In addition, a cavum Vergae and reduced periventricular bilateral white matter are noted. d Sagittal and e, Axial T2-weighted images of a 15-year-old girl with cerebellar agenesis reveal almost complete absence of cerebellar tissue except for a rudimentary structure projecting posterior to the inferior colliculi and lateral to the brainstem. The pons is markedly hypoplastic and the posterior fossa is enlarged (reprinted with permission from Poretti A et al., Eur J Paediatric Neurol, 2009). f Sagittal T1- and g Axial T2-weighted images of a 1-year-old child with pontocerebellar hypoplasia type 2 and TSEN54 mutations show marked hypoplasia and reduction in the size of the cerebellar hemispheres with relative preservation of the midline vermis, resulting in a characteristic “dragonfly” appearance (reprinted with permission from Bosemani T et al., Radiographics, 2015). h Axial and i, Coronal T2-weighted images of an 11-month-old child with Poretti-Boltshauser syndrome and LAMA1 mutations reveal bilateral cerebellar dysplasia as abnormal cerebellar foliation, white matter arborization, and gray-white matter junction and multiple cortical/subcortical cysts located within the cerebellar vermis (mostly anterior and superior part) and both cerebellar hemispheres (mostly posterior and superior parts) (reprinted with permission from Poretti A et al., Cerebellum, 2014). j Sagittal and k, Axial T2-weighted images of 15-year-old patient with neurofibromatosis type 1 and cerebellar dysmorphia show enlargement of the left cerebellar hemisphere with enlarged interfolial spaces and bulky appearance of its posteromedial part, which crosses the midline. In addition, a plexiform neurofibroma is seen in the left soft tissue (reprinted with permission from Toelle SP et al., Cerebellum, 2015). l Sagittal T2-weighted image of a 5-year-old child with ataxia oculomotor apraxia type 1 disease and marked cerebellar atrophy as enlargement of the interfolial spaces