Posterior iliac horns are seen in –
Nail-Patella syndrome is characterized by : 

Small or absent nails                  
Overextension of joints  
Small or absent patella    
Posterior iliac horns  
Renal anomalies 
Skin laxity
Hyperhidrosis
Fisher's syndrome
Crouzan syndrome
Nail patella syndrome
Pierre Robbins syndrome
Nail patella syndrome