However, these studies did not include such vital factors associated with osteoporosis as bone turnover markers, including parathyroid hormone (PTH), C-terminal telopeptide of type I collagen (β-CTX), N-terminal propeptides of type I procollagen (PINP), osteocalcin (OC), serum 25-hydroxy vitamin D3 (25-OH-D3) levels, and alkaline phosphatase (ALP). The gene discussed is PTH; the disease is osteoporosis.