In girls with idiopathic central precocious puberty the risk of subnormal growth velocity appears highest at the 3rd year of gonadotropin-releasing hormone analog treatment in those patients with, at the time of diagnosis, pubic hair in conjunction with high baseline and peak luteinizing hormone (LH) and advanced bone age and excessive LH suppression on follow-up. The gene discussed is PLOD1; the disease is central precocious puberty.