Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Primary melanoma of the central nervous system ?
    ### Response:
    What causes primary melanoma of the central nervous system? Although the exact cause of this condition is unknown, researchers have identified somatic mutations in the the GNAQ gene in 7 of 19 patients (37 percent) with primary malignant melanocytic tumors of the central nervous system.
    