Inactivation of FAM20B caused a reduction of chondroitin sulfate (CS) in AF. IHC detection of CS in the IVDs of E16.5 (A, B), P0 (C, D), 1-week-old (E, F) and 3-week-old (G, H) control and cKO mice (representative images from at least 3 mice for each group at each time point). A1, B1, C1, D1, E1, F1, G1 and H1 were the higher magnification views of the black boxes in A, B, C, D, E, F, G and H respectively (Bars in the A, B, C, D, E1, F1, G1, H1 = 50 μm, Bars in the A1, B1, C1, D1 = 20 μm, Bars in the E, F, G, H = 100 μm). Note the reduction of CS in the IVDs of cKO mice. CS was even completely lost in some areas of AF in cKO mice.