INTRODUCTIONAlagille syndrome is an autosomal dominant disorder resulting from a mutation in the JAG1 gene in 95% of cases, and less than 1% of cases have a mutation in the gene NOTCH2. (Cire, Chard, Pinette and Cartin, 2013). Originally it was thought to occur in 1 in 70,000 live births, but current research estimates that this phenomenon is more common, at approximately 1 in 30,000 live births. For Alagille syndrome to be definitively diagnosed , the “class criteria” must be met. Without meeting the “classical criteria”, which will be explained in more detail below, Alagille syndrome cannot be diagnosed. Using ultrasound during pregnancy can help screen fetuses for this condition if there is a family history and the sonographer knows what to look for. DISCUSSION As mentioned above, the “classic criteria” must be met in order to definitively diagnose a patient. suffering from Alagille syndrome (AGS). Turnpenny and Ellard (2012) define "classic criteria" as: cholestasis due to bile duct insufficiency, congenital heart disease (most commonly peripheral pulmonary artery stenosis), face (mild but recognizable dysmorphic features), skeleton (abnormal segmentation, most commonly in the form of butterfly vertebrae) and the eye (anterior chamber defects, most commonly posterior embryotoxon). (p. 252) Along with these criteria, there must be a parent positive for the JAG1 or NOTCH2 gene mutation since it is an autosomal dominant disorder, and the disease will often be seen in the parent carrying the genetic mutation. It is important to explain the different aspects of each of the criteria necessary for the diagnosis of AGS so that the level of severity can be determined. The most important part of AGS to pay attention to...... middle of paper ..... .performed by AGS.Works CitedMolinero-Herguedas, E., Labrador-Fuster, T., Rios -Lazaro, M. and Carmaniu-Tobal, J. (2008). Aortic aneurysm in Alagille syndrome. Revista Española de Cardiología, 658-659.Murthy, GS, Baldev, RS, Das, A., Thapa, B., Duseja, AK, Dhiman, RK, et al. (2012, June). Alagille syndrome: a rare disease in adolescents. Springer Science, 3035-3037. Schneider, B.L. (May 2012). Liver transplantation for Alagille syndrome: the jagged edge. American Association for the Study of Liver Diseases, 878-880. Turnpenny, P.D. and Ellard, S. (2012). Alagille syndrome: pathogenesis, diagnosis and management. European Journal of Human Genetics, 251-257.Wax, JR, Chard, R., Pinette, MG and Cartin, A. (November 2013). Two-dimensional and three-dimensional prenatal ultrasound diagnosis of Alagille syndrome. Journal of Clinical Ultrasound , 1-4.