Question: What is (are) Alagille syndrome ?
Answer: Alagille syndrome is an inherited disorder in which a person has fewer than the normal number of small bile ducts inside the liver. It is a complex disorder that can affect other parts of the body including the heart, kidneys, blood vessels, eyes, face, and skeleton. Symptoms, including jaundice, pale, loose stools, and poor growth, typically develop in the first 2 years of life. Symptoms and symptom severity varies, even among people in the same family. Alagille syndrome is caused by mutations in the JAG1 and NOTCH2 genes. It is inherited in an autosomal dominant pattern. Treatment is symptomatic and supportive. In severe cases, liver transplant may be necessary.
Source: GARD

Question: What are the symptoms of Alagille syndrome ?
Answer: What are the signs and symptoms of Alagille syndrome? Alagille syndrome is a complex multisystem disorder involving the liver, heart, eyes, face, and skeleton. Symptoms typically present in infancy or early childhood. The severity of the disorder varies among affected individuals, even within the same family. Symptoms range from so mild as to go unnoticed to severe enough to require heart and/or liver transplants. One of the major features of Alagille syndrome is liver damage caused by abnormalities in the bile ducts. These ducts carry bile (which helps to digest fats) from the liver to the gallbladder and small intestine. In Alagille syndrome, the bile ducts may be narrow, malformed, and reduced in number. This results in a build-up of bile causing scarring that prevents the liver from working properly. This may lead to jaundice, itchy skin, and deposits of cholesterol in the skin (xanthomas). Alagille syndrome is also associated with several heart problems, including impaired blood flow from the heart into the lungs (pulmonic stenosis). Other heart-related problems include a hole between the two lower chambers of the heart (ventricular septal defect) and a combination of heart defects called tetralogy of Fallot. People with Alagille syndrome may also have distinctive facial features (including a broad, prominent forehead; deep-set eyes; and a small, pointed chin), problems with the blood vessels within the brain and spinal cord (central nervous system) and the kidneys, and an unusual butterfly shape of the bones of the spinal column (vertebrae). Detailed information about the symptoms associated with Allagille syndrome can be accessed through the National Digestive Diseases Information Clearinghouse (NDDIC) and GeneReviews. The Human Phenotype Ontology provides the following list of signs and symptoms for Alagille syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Biliary tract abnormality 90% Corneal dystrophy 90% Hepatomegaly 90% Ventricular septal defect 90% Abnormal form of the vertebral bodies 50% Abnormal nasal morphology 50% Abnormality of the pinna 50% Coarse facial features 50% Frontal bossing 50% Intrauterine growth retardation 50% Pointed chin 50% Round face 50% Spina bifida occulta 50% Telangiectasia of the skin 50% Vertebral segmentation defect 50% Abnormality of chromosome segregation 7.5% Abnormality of the pulmonary artery 7.5% Abnormality of the pupil 7.5% Abnormality of the ribs 7.5% Abnormality of the ulna 7.5% Abnormality of the ureter 7.5% Atria septal defect 7.5% Clinodactyly of the 5th finger 7.5% Cognitive impairment 7.5% Cryptorchidism 7.5% Decreased corneal thickness 7.5% Deeply set eye 7.5% Delayed skeletal maturation 7.5% Hypertelorism 7.5% Hypertension 7.5% Intellectual disability, mild 7.5% Malar flattening 7.5% Nephrotic syndrome 7.5% Renal hypoplasia/aplasia 7.5% Short distal phalanx of finger 7.5% Short philtrum 7.5% Strabismus 7.5% Areflexia - Autosomal dominant inheritance - Axenfeld anomaly - Band keratopathy - Broad forehead - Butterfly vertebral arch - Cataract - Chorioretinal atrophy - Cirrhosis - Coarctation of aorta - Depressed nasal bridge - Elevated hepatic transaminases - Exocrine pancreatic insufficiency - Failure to thrive - Hemivertebrae - Hepatocellular carcinoma - Hypercholesterolemia - Hypertriglyceridemia - Hypoplasia of the ulna - Incomplete penetrance - Infantile onset - Long nose - Macrotia - Microcornea - Multiple small medullary renal cysts - Myopia - Papillary thyroid carcinoma - Peripheral pulmonary artery stenosis - Pigmentary retinal deposits - Posterior embryotoxon - Prolonged neonatal jaundice - Reduced number of intrahepatic bile ducts - Renal dysplasia - Renal hypoplasia - Renal tubular acidosis - Specific learning disability - Stroke - Tetralogy of Fallot - Triangular face - Upslanted palpebral fissure - Vesicoureteral reflux - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD