Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Familial osteochondritis dissecans ?
    ### Response:
    What causes osteochondritis dissecans? In most cases, the exact underlying cause of osteochondritis dissecans is not completely understood. Scientists suspect that it may be due to decreased blood flow to the end of the affected bone, which may occur when repetitive episodes of minor injury and/or stress damage a bone overtime.
    