Pathophysiology of Paget's Disease of Bone

Inclusion Criteria for Cases: * Men and women between the ages of 18-99 years who have evidence of active Paget's disease of bone as clinically and/or radiographically defined by: * Increased serum alkaline phosphatase or increased serum collagen type 1 c-telopeptide (CTX) or increase in urinary pyridinoline at diagnosis * AND history of at least one of the following signs/symptoms: Pagetoid lesions(s) on x-ray/CT/MRI, increased uptake of radioactive substance by bone scan, bone pain, fracture, hearing loss, headache, hypercalcemia, or bony deformity. Inclusion criteria for controls: * Men and women between the ages of 18-99 years who match age within 5 years of cases and gender who do NOT have evidence of Paget's disease of bone as defined by: * No bone pain or bony deformity * Normal serum alkaline phosphatase Exclusion Criteria: * Osteosarcoma or other blastic bony metastases alone * Fibrous dysplasia of bone * Hyperostosis frontalis interna * All men and women \< 18 years or \> 99 years * Pregnancy (women) determined by self-report * Current use of oral contraceptive tablets or Depo-Provera™ (women) * Current use of hormone replacement therapy * Creatinine clearance \< 60 ml/min./1.73 m2 by Cockcroft-Gault based on most recent serum creatinine level (if greater than 1 year since last assessment, will be measured on collected blood sample to verify eligibility) * Current smoking or tobacco use * Alcohol use greater than 3 units daily * Use of thiazolidinediones within the last year * Use of medications known to impact bone and mineral metabolism, including use of a bisphosphonate in the last 11 months; ever use of teriparatide or denosumab; use of calcitonin, selective estrogen receptor modulators (SERMs), or estrogen within the past 6 months, prednisone \> 5 mg for over 10 days in the last three months, anti-epileptic medications (e.g. phenytoin, carbamezapine, phenobarbitol, and primidone); current or use within the past year of aromatase inhibitors; leuprolide; histrelin * History of a thyroid problem that is currently uncontrolled as defined by most recent thyroid stimulating hormone levels \< 0.1 microIU/mL (if greater than 6 months since last assessment, will be measured on collected blood sample to verify eligibility) * Other known metabolic or structural bone disease other than low bone density (e.g. hyperparathyroidism, multiple myeloma, sarcoid or other granulomatous disease, celiac disease, osteopetrosis, osteomalacia, osteitis fibrosa cystica) * Other significant medical illness (heart disease, pulmonary disease, inflammatory bowel disease, malignancy other than ductal carcinoma in situ (DCIS) or non-melanoma skin cancer, rheumatologic conditions including rheumatoid arthritis, systemic lupus, renal disease requiring dialysis, etc.) * Inability to understand and provide informed consent.