Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy ?
    ### Response:
    CARASIL is caused by mutations in the HTRA1 gene. This gene provides instructions for making an enzyme that is found in many of the body's organs and tissues. One of the major functions of the HTRA1 enzyme is to regulate signaling by proteins in the transforming growth factor-beta (TGF-) family.
    