We wished to quantify cerebellar Purkinje cells in the MIA model because Purkinje cell dropout is a characteristic feature of certain primary mitochondrial disorders such as Alpers syndrome [51] and because Purkinje cell dropout in lobule VII of the cerebellar vermis is also a feature of decreased FMRP expression in Fragile X Syndrome [52] and in the MIA mouse model [53]. This evidence concerns the gene FMR1 and fragile X syndrome.