Below is an instruction from Human. Write a response.
    ### Instruction:
    How many people are affected by Klinefelter syndrome ?
    ### Response:
    Klinefelter syndrome affects 1 in 500 to 1,000 newborn males. Most variants of Klinefelter syndrome are much rarer, occurring in 1 in 50,000 or fewer newborns.  Researchers suspect that Klinefelter syndrome is underdiagnosed because the condition may not be identified in people with mild signs and symptoms.
    