COL11A1 and Hip dysplasia: To explore the correlation between Col11a1 and DDH development, we collected 21 DDH cases (KL score = 1, three patients; KL socre = 2, six patients; KL score = 3, six patients; KL score = 4, six patients) and six control patients (KL score = 0, three patients; KL score = 1, three patients).