What are the genetic changes related to frontotemporal dementia with parkinsonism-17 ?
FTDP-17 is caused by mutations in the MAPT gene. This gene is located on chromosome 17, which is how the disease got its name.  The MAPT gene provides instructions for making a protein called tau. This protein is found throughout the nervous system, including in nerve cells (neurons) in the brain. It is involved in assembling and stabilizing microtubules, which are rigid, hollow fibers that make up the cell's structural framework (the cytoskeleton). Microtubules help cells maintain their shape, assist in the process of cell division, and are essential for the transport of materials within cells.  Mutations in the MAPT gene disrupt the normal structure and function of tau. The defective protein assembles into abnormal clumps within neurons and other brain cells. However, it is unclear what effect these clumps have on cell function and survival. FTDP-17 is characterized by the gradual death of cells in areas of the brain called the frontal and temporal lobes. The frontal lobes are involved in reasoning, planning, judgment, and problem-solving, while the temporal lobes help process hearing, speech, memory, and emotion. A loss of cells in these brain regions leads to personality changes, speech difficulties, and the other features of FTDP-17.  FTDP-17 is one of several related diseases known as tauopathies, which are characterized by an abnormal buildup of tau in the brain.