Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to familial idiopathic basal ganglia calcification ?
    ### Response:
    Mutations in the SLC20A2 gene cause nearly half of all cases of FIBGC. A small percentage of cases are caused by mutations in the PDGFRB gene. Other cases of FIBGC appear to be associated with changes in chromosomes 2, 7, 9, and 14, although specific genes have yet to be identified.
    