Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to multiple sclerosis ?
    ### Response:
    Although the cause of multiple sclerosis is unknown, variations in dozens of genes are thought to be involved in multiple sclerosis risk. Changes in the HLA-DRB1 gene are the strongest genetic risk factors for developing multiple sclerosis. Other factors associated with an increased risk of developing multiple sclerosis include changes in the IL7R gene and environmental factors, such as exposure to the Epstein-Barr virus, low levels of vitamin D, and smoking.
    