causes of allagile syndrome
A problem with the JAG1 gene (usually a mutation in, but sometimes a deletion of it) causes more than 90% of Alagille syndrome cases. In 2% to 3% of cases, a mutation on the NOTCH2 gene causes Alagille syndrome. In around 3% of people with Alagille syndrome, the genetic cause is not known. The JAG1 and NOTCH2 genes give your cells instructions to make proteins that create a communication pathway between cells so the cells know when to build certain parts of the body during fetal development. When there is a mutation on either of these genes or a deletion of genetic material on chromosome 20 that includes JAG1, your cells don’t have the instructions they need to do their job, which causes symptoms of the condition like structural heart defects, narrow bile ducts and skeletal abnormalities.