Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) juvenile primary osteoporosis ?
    ### Response:
    Juvenile primary osteoporosis is a skeletal disorder characterized by thinning of the bones (osteoporosis) that begins in childhood. Osteoporosis is caused by a shortage of calcium and other minerals in bones (decreased bone mineral density), which makes the bones brittle and prone to fracture.
    