Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Pearson marrow-pancreas syndrome ?
    ### Response:
    Pearson marrow-pancreas syndrome is caused by defects in mitochondria, which are structures within cells that use oxygen to convert the energy from food into a form cells can use. This process is called oxidative phosphorylation. Although most DNA is packaged in chromosomes within the nucleus (nuclear DNA), mitochondria also have a small amount of their own DNA, called mitochondrial DNA (mtDNA).
    