Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to hereditary sensory and autonomic neuropathy type II ?
    ### Response:
    There are two types of HSAN2, called HSAN2A and HSAN2B, each caused by mutations in a different gene. HSAN2A is caused by mutations in the WNK1 gene, and HSAN2B is caused by mutations in the FAM134B gene. Although two different genes are involved, the signs and symptoms of HSAN2A and HSAN2B are the same.
    