SMARCB1 and neoplasm: Such an observation is consistent with the lack of tumour phenotype in Smarcb1flox/flox;Atoh1-Cre model40; this model demonstrates that Smarcb1-deficient granule cell precursors fail to develop and lead to severe cerebellum hypoplasia, indicating that AT/RT do not arise from granule cell precursors but from a distinct, developmentally restricted cell population.