The phenotype of young mice. A, Double staining with alcian blue and alizarin red of the whole skeleton in newborn mice. Scale bar = 1 cm. B, Growth curves determined by the body weight of male wild-type (WT) and Col2-Ugcg−/− littermates. Weight did not differ significantly between genotypes (n = 10 per group). Data shown are mean ± SEM. Females of both genotypes showed similar skeletal development and growth (data not shown). C, Histological findings of the knee joints in 4-week-old mice. Safranin O (Saf-O) staining, toluidine blue (TB) staining, and immunostaining of type II collagen (Col2) and type X collagen (Col10) were performed in each genotype (upper: articular cartilage, lower: growth plate of tibia). Scale bars = 100 µm.