Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) 48,XXYY syndrome ?
    ### Response:
    48,XXYY syndrome is a chromosomal condition, characterized by the presence of an extra X and Y chromosome in males, that causes medical and behavioral problems. 48,XXYY can be considered a variant of Klinefelter syndrome. Individuals with 48,XXYY are usually considerably tall with small testes that do not function normally leading to infertility.
    