Below is an instruction from Human. Write a response.
    ### Instruction:
    How many people are affected by cartilage-hair hypoplasia ?
    ### Response:
    Cartilage-hair hypoplasia occurs most often in the Old Order Amish population, where it affects about 1 in 1,300 newborns. In people of Finnish descent, its incidence is approximately 1 in 20,000. Outside of these populations, the condition is rare, and its specific incidence is not known.
    