Idiopathic juvenile osteoporosis (IJO) is a primary condition of bone demineralization childhood or adolescence that presents with pain in the back and extremities, walking difficulties, multiple fractures, and radiological evidence of osteoporosis. Onset usually occurs in the prepubertal period, between 8 and 12 years of age. The disease is idiopathic juvenile osteoporosis (MONDO_0019409, a Monarch Disease Ontology id). Also known as: IJO, Ijo, Paediatric osteoporosis, Pediatric osteoporosis, idiopathic osteoporosis, juvenile osteoporosis.