PTPRC and cerebellar ataxia: Fluorescence-activated cell sorting (FACS) analysis of skin before and after S. aureus infection also showed an increase in the population of preadipocytes in the dermis of Cemip−/− mice as defined by CD31-negative, CD45-negative, platelet-derived growth factor receptor-α (PDGFRα)-positive, and spinocerebellar ataxia type 1 (SCA1)-positive cells (Figures 3F and 3G).