Based on the mRNA distribution pattern, we performed immunohistopathological analysis of the cerebellum and hippocampus extensively. Despite the high level of expression of ADAM22 mRNAs in the cerebellar granule cells, granule cell layer was normally formed and Purkinje cell morphology (calbindin-staining) of the mutant mouse looked intact (Figs. 4A–D). Hippocampal formation was also normally formed (Figs. 4I–J). These results suggest that neuronal cell migration was not impaired in the mutant mouse. Myelin-formation detected by MBP (myelin basic protein) staining of the mutant in the cerebellum (Fig. 4H) and spinal cord (Fig. 4L) was also indistinguishable with the wild-type littermate (Figs. 4G,K). In summary, we could not find any signs of abnormalities in the mutant mouse brain by the light microscopic examination.