Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to familial HDL deficiency ?
    ### Response:
    Mutations in the ABCA1 gene or the APOA1 gene cause familial HDL deficiency. The proteins produced from these genes work together to remove cholesterol and phospholipids from cells.  The ABCA1 gene provides instructions for making a protein that removes cholesterol and phospholipids from cells by moving them across the cell membrane.
    