What are the genetic changes related to cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy ?
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. TGF- signaling is essential for many critical cell functions. It also plays an important role in the formation of new blood vessels (angiogenesis).  In people with CARASIL, mutations in the HTRA1 gene prevent the effective regulation of TGF- signaling. Researchers suspect that abnormally increased TGF- signaling alters the structure of small blood vessels, particularly in the brain. These blood vessel abnormalities (described as arteriopathy) greatly increase the risk of stroke and lead to the death of nerve cells (neurons) in many areas of the brain. Dysregulation of TGF- signaling may also underlie the hair loss and back pain seen in people with CARASIL, although the relationship between abnormal TGF- signaling and these features is less clear.