The signs and symptoms of Alagille syndrome and their severity vary, even among people in the same family sharing the same gene mutation.
                
Liver
                
In some people, problems in the liver may be the first signs and symptoms of the disorder. These signs and symptoms can occur in children and adults with Alagille syndrome, and in infants as early as the first 3 months of life.
                
Jaundice. Jaundicewhen the skin and whites of the eyes turn yellowis a result of the liver not removing bilirubin from the blood. Bilirubin is a reddish-yellow substance formed when hemoglobin breaks down. Hemoglobin is an iron-rich protein that gives blood its red color. Bilirubin is absorbed by the liver, processed, and released into bile. Blockage of the bile ducts forces bilirubin and other elements of bile to build up in the blood.
                
Jaundice may be difficult for parents and even health care providers to detect. Many healthy newborns have mild jaundice during the first 1 to 2 weeks of life due to an immature liver. This normal type of jaundice disappears by the second or third week of life, whereas the jaundice of Alagille syndrome deepens. Newborns with jaundice after 2 weeks of life should be seen by a health care provider to check for a possible liver problem.
                
Dark urine and gray or white stools. High levels of bilirubin in the blood that pass into the urine can make the urine darker, while stool lightens from a lack of bilirubin reaching the intestines. Gray or white bowel movements after 2 weeks of age are a reliable sign of a liver problem and should prompt a visit to a health care provider.
                
Pruritus. The buildup of bilirubin in the blood may cause itching, also called pruritus. Pruritus usually starts after 3 months of age and can be severe.
                
Xanthomas. Xanthomas are fatty deposits that appear as yellow bumps on the skin. They are caused by abnormally high cholesterol levels in the blood, common in people with liver disease. Xanthomas may appear anywhere on the body. However, xanthomas are usually found on the elbows, joints, tendons, knees, hands, feet, or buttocks.
                
Other Signs and Symptoms of Alagille Syndrome
                
Certain signs of Alagille syndrome are unique to the disorder, including those that affect the vertebrae and facial features.
                
Face. Many children with Alagille syndrome have deep-set eyes, a straight nose, a small and pointed chin, large ears, and a prominent, wide forehead. These features are not usually recognized until after infancy. By adulthood, the chin is more prominent.
                
Eyes. Posterior embryotoxon is a condition in which an opaque ring is present in the cornea, the transparent covering of the eyeball. The abnormality is common in people with Alagille syndrome, though it usually does not affect vision.
                
Skeleton. The most common skeletal defect in a person with Alagille syndrome is when the shape of the vertebraebones of the spinegives the appearance of flying butterflies. This defect, known as "butterfly" vertebrae, rarely causes medical problems or requires treatment.
                
Heart and blood vessels. People with Alagille syndrome may have the following signs and symptoms having to do with the heart and blood vessels:
                
- heart murmuran extra or unusual sound heard during a heartbeat. A heart murmur is the most common sign of Alagille syndrome other than the general symptoms of liver disease.1 Most people with Alagille syndrome have a narrowing of the blood vessels that carry blood from the heart to the lungs.1 This narrowing causes a murmur that can be heard with a stethoscope. Heart murmurs usually do not cause problems.  - heart walls and valve problems. A small number of people with Alagille syndrome have serious problems with the walls or valves of the heart. These conditions may need treatment with medications or corrective surgery.  - blood vessel problems. People with Alagille syndrome may have abnormalities of the blood vessels in the head and neck. This serious complication can lead to internal bleeding or stroke. Alagille syndrome can also cause narrowing or bulging of other blood vessels in the body.
                
Kidney disease. A wide range of kidney diseases can occur in Alagille syndrome. The kidneys are two bean-shaped organs, each about the size of a fist, that filter wastes and extra fluid from the blood. Some people have small kidneys or have cystsfluid-filled sacsin the kidneys. Kidney function can also decrease.