Bergman glia in MPS IIIB dogs displayed much thicker processes than in corresponding age-matched unaffected controls (Fig. 8), and a distinctive band of GFAP immunostaining was evident at the interface between granule and molecular layers, marking where Purkinje cells normally sit (Fig. 8, Purkinje layer). The gene discussed is GFAP; the disease is mucopolysaccharidosis type 3B.