What is the life expectancy of someone with Alagille syndrome?
Many people with Alagille syndrome have only mild symptoms and can lead normal lives with normal life expectancy. However, others have severe and even life-threatening complications such as liver failure, serious heart defects, and bleeding or stroke due to blood vessel problems.
What does the JAG1 gene do?
The JAG1 gene provides instructions for making a protein called Jagged-1, which is involved in an important pathway by which cells can signal to each other. The Jagged-1 protein is inserted into the membranes of certain cells.
Does Alagille syndrome cause retardation?
Alagille syndrome is an autosomal dominant disorder with variable expression. Associated abnormalities include those of the liver, heart, eye, skeleton, and kidneys and characteristic facial features. Mild-to-moderate mental retardation also may be present.
Where is the JAG1 gene?
human chromosome 20
Located on human chromosome 20, the JAG1 gene is expressed in multiple organ systems in the body and causes the autosomal dominant disorder Alagille syndrome (ALGS) resulting from loss of function mutations within the gene. JAG1 has also been designated as CD339 (cluster of differentiation 339).
How rare is Alagille?
The incidence of Alagille syndrome has been estimated to be approximately 1 in 30,000-45,000 individuals in the general population.
Is Alagille syndrome hereditary?
Key points. Alagille syndrome is a genetic disorder in which you have fewer bile ducts than normal in your liver. Alagille syndrome can be passed from parent to child or happen naturally. Alagille syndrome not only affects the liver, it can also cause skin, heart, facial, kidney, and eye abnormalities.
Which type of chromosomal mutation will lead to Alagille syndrome?
Alagille syndrome is predominately caused by changes in a gene called Jagged1 located on chromosome 20. In 3 to 5 percent of cases, the entire gene is deleted (missing) from one copy of chromosome 20.
What type of mutation is Alagille syndrome?
Alagille syndrome is caused by mutations in one of two genes – the JAG1 gene or the NOTCH2 gene. Mutations of the JAG1 gene have been identified in more than 88 percent of cases. Mutations in the NOTCH2 gene account for less than 1 percent of cases. These mutations are inherited in an autosomal dominant pattern.
Does Alagille syndrome affect the brain?
People with Alagille syndrome may have distinctive facial features including a broad, prominent forehead; deep-set eyes; and a small, pointed chin. The disorder may also affect the blood vessels within the brain and spinal cord (central nervous system) and the kidneys.
Is Alagille syndrome curable?
This causes a decrease in the flow of bile out of the liver which leads to reduced digestion of dietary fat and vitamins (A, D, E, K). The key clinical features are poor growth, itching, and progressive liver injury. There is no specific treatment for Alagille syndrome.
Is Alagille syndrome detectable prior to birth?
Although Alagille syndrome is present from birth, it is often not diagnosed until later in childhood, particularly in less severe cases with few symptoms. To diagnose Alagille syndrome, a clinician will typically conduct a physical examination and order some or all of the following tests: blood test. urinalysis.
What causes Alagille syndrome?
What causes Alagille syndrome? Gene mutations link cause Alagille syndrome. Mutations of a gene called JAG1 cause most cases of Alagille syndrome. Mutations of a gene called NOTCH2 cause 1 to 2 percent of cases of Alagille syndrome.
How many people have Alagille?
It appears in one out of 70,000 babies and occurs in both sexes. However, about half the time, the mutation is new and not from a parent.
What is the genetic cause of Alagille syndrome?
Alagille syndrome is caused by mutations in one of two genes – the JAG1 gene or the NOTCH2 gene. Mutations of the JAG1 gene have been identified in more than 88 percent of cases. Mutations in the NOTCH2 gene account for less than 1 percent of cases. These mutations are inherited as autosomal dominant traits.
What is the pathophysiology of Alagille?
Alagille Syndrome is an autosomal-dominant inherited disease caused by mutations in the JAG1 and NOTCH2 genes. First described by its characteristic intrahepatic bile duct hypoplasia, Alagille Syndrome is now known to impact multiple organ systems2.
What are the renal abnormalities of Alagille syndrome?
Kidney abnormalities may be more prevalent in individuals with Alagille syndrome caused by mutations in the NOTCH2 gene and include abnormally small kidneys, the presence of cysts on the kidneys and decreased or impaired kidney function.
What are the symptoms of Alagille syndrome?
Additional symptoms include heart murmurs, congenital heart defects, vertebral (back bone) differences, thickening of the ring that normally lines the cornea in the eye (posterior embryotoxon) and distinctive facial features. Most people with Alagille syndrome have changes (mutations) in one copy of the JAG1 gene.