Question: What are the genetic changes related to Walker-Warburg syndrome ?
Answer: Walker-Warburg syndrome can be caused by mutations in one of several genes, including POMT1, POMT2, ISPD, FKTN, FKRP, and LARGE. The proteins produced from these genes modify another protein called alpha ()-dystroglycan; this modification, called glycosylation, is required for -dystroglycan to function. The -dystroglycan protein helps anchor the structural framework inside each cell (cytoskeleton) to the lattice of proteins and other molecules outside the cell (extracellular matrix). In skeletal muscles, the anchoring function of -dystroglycan helps stabilize and protect muscle fibers. In the brain, it helps direct the movement (migration) of nerve cells (neurons) during early development. Mutations in these genes prevent glycosylation of -dystroglycan, which disrupts its normal function. Without functional -dystroglycan to stabilize muscle cells, muscle fibers become damaged as they repeatedly contract and relax with use. The damaged fibers weaken and die over time, leading to progressive weakness of the skeletal muscles. Defective -dystroglycan also affects the migration of neurons during the early development of the brain. Instead of stopping when they reach their intended destinations, some neurons migrate past the surface of the brain into the fluid-filled space that surrounds it. Researchers believe that this problem with neuronal migration causes cobblestone lissencephaly in children with Walker-Warburg syndrome. Less is known about the effects of the gene mutations in other parts of the body, including the eyes. Mutations in the POMT1, POMT2, ISPD, FKTN, FKRP, and LARGE genes are found in only about half of individuals with Walker-Warburg syndrome. Other genes, some of which have not been identified, are likely involved in the development of this condition. Because Walker-Warburg syndrome involves a malfunction of -dystroglycan, this condition is classified as a dystroglycanopathy.
Source: GHR