The Wnt Pathway
Introduction
Scientists zeroed in on the gene responsible for multiple sclerosis, a disease in which the body's immune system attacks the protective sheath around nerve cells to the extent of interfering with nerve communications. A gene called Tcf4 was found to activate biochemical reactions (the Wnt pathway) that delayed the sheath's repair, said the study in the July 1 issue of Genes and development. A prolonged delay made the body incapable of growing the sheath back, leading to progressive deterioration of the nerves.
Source
Down to Earth, August 2009