Phase II Study of Alendronate Sodium in Children With High-Turnover Idiopathic Juvenile Osteoporosis

Eligibility Criteria: * 5-14 years of age * Weight 20 kg or greater * History of one or more atraumatic fracture * Sexual development no greater than Tanner II * Osteoporosis by DXA (Diagnosis of high-turnover osteoporosis with no underlying cause (e.g., malignancy, hyperthyroidism, hyperparathyroidism, or vitamin D intoxication) Inclusion Criteria: * Male and female children with a history of one or more atraumatic fractures, or evidence of one or more compression fractures on radiographs of the spine (reduction of \>20%). * Bone mineral density by DXA at 2 standard deviations (SD) below normal mean for age (Z-score at least 2 SD below normal mean at the lumbar spine or hip) * Parental consent (and patient assent after age 12 years) to participate in the study. * Sexual development at Tanner stage II or less (Prepubertal stage) * Weight 20kg and more Exclusion Criteria: * History of severe gastritis or reflux * Marked kyphoscoliosis or inability to sit or stand for at least 30 minutes. * Abnormalities of the esophagus that delay emptying (e.g., strictures or achalasia) * Hypersensitivity to bisphosphonates * Uncorrected hypocalcemia * History of gastric or duodenal ulcers * Renal dysfunction as indicated by serum Creatinine greater than 1.5 mg/dL * Liver dysfunction as indicated by serum SGPT greater than 2 times upper limit of normal for age or serum total bilirubin greater than 2.0 mg/dL * Diagnosis of osteogenesis imperfecta (including family history) or blue sclerae or deafness * Diagnosis of active rickets, osteomalacia, or bone alkaline phosphatase \> 2 times normal for age * Severe gastritis or reflux * Pregnancy * Anorexia Nervosa * Prior/Concurrent Therapy- * Prior course of prednisone allowed * No concurrent prednisone except inhaled steroids * No concurrent high-dose glucocorticoids * No concurrent salmon calcitonin * No other concurrent bisphosphonates * No concurrent long-term anti-seizure medication