INTRODUCTION Alagille syndrome is an autosomal dominant condition resulting from a mutation in the JAG1 gene in 95% of cases, and less than 1% of cases have a mutation in the NOTCH2 gene. (Cera, Bietola, Pinette and Cartin, 2013). It was initially said to occur at 1 in 70,000 live births, but current research believes the occurrence is more common at around 1 in 30,000 live births. In order for Alagille syndrome to be definitively diagnosed, the “class criteria” must be met. Without meeting the “classic criteria,” which will be explained in more detail below, Alagille syndrome cannot be diagnosed. Using ultrasound during a pregnancy can help screen fetuses for this condition if there is a family history and the sonographer knows what to look for. DISCUSSIONS As mentioned above, the "classical criteria" must be met in order to definitively diagnose a patient with Alagille syndrome (AGS). Turnpenny and Ellard (2012) define the “Classic Criteria” as: cholestasis due to bile duct paucity, congenital heart disease (most commonly peripheral pulmonary artery stenosis), face (mild but recognizable dysmorphic features), the 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 who is positive for the JAG1 or NOTCH2 gene mutation as this is an autosomal dominant condition and the condition will often be found in the parent with the genetic mutation. It is important to explain the different aspects of each of the criteria needed to diagnose AGS so that the level of severity can be determined. The most important part of the AGS to pay attention to... middle of the paper... .influenced by AGS.Works CitedMolinero-Herguedas, E., Labrador-Fuster, T., Rios-Lazaro, M., & Carmaniu- Tobal, J. (2008). Aortic aneurysm in Alagille syndrome. Revista Española de Cardiología, 658-659.Murthy, G.S., Baldev, R.S., Das, A., Thapa, B., Duseja, A.K., Dhiman, R.K., et al. (2012, June). Alagille syndrome: a rare disease in an adolescent. Springer Science, 3035-3037. Shneider, B. L. (2012, May). Liver Transplant for Alagille Syndrome: The Jagged Edge. American Association for the Study of Liver Diseases, 878-880. Turnpenny, P. D., & Ellard, S. (2012). Alagille syndrome: pathogenesis, diagnosis and management. European Journal of Human Genetics, 251-257.Wax, J.R., Chard, R., Pinette, M.G., & Cartin, A. (2013, November). Two- and three-dimensional prenatal ultrasound diagnosis of Alagille syndrome. Journal of Clinical Ultrasound , 1-4.