Alagille Syndrome
Also known as: ALGS, Arteriohepatic Dysplasia, Watson-Miller Syndrome
Alagille syndrome is a genetic disorder that affects multiple organ systems in the body, including the liver, heart, kidneys, and eyes. The most prominent feature of Alagille syndrome is liver damage caused by abnormalities in the bile ducts. Bile, a fluid produced by the liver, aids in digestion. In individuals with Alagille syndrome, the bile ducts may be narrowed, malformed, or reduced in number, leading to bile buildup in the liver (cholestasis) and subsequent liver damage. Other common features include heart defects, butterfly vertebrae, characteristic facial features, and kidney abnormalities.
Imagine your liver has tiny tubes that help it clean your body. In Alagille syndrome, these tubes are messed up, so the liver can't clean properly. This can cause yellow skin, itchy skin, and other problems with your heart, eyes, and bones. Doctors can help with medicine and sometimes surgery to make you feel better.
Signs & Symptoms
- Jaundice (yellowing of the skin and eyes)
- Pruritus (severe itching)
- Xanthomas (cholesterol deposits in the skin)
- Hepatomegaly (enlarged liver)
- Cardiac murmur (heart defect)
- Butterfly vertebrae (spinal abnormality)
- Posterior embryotoxon (eye abnormality)
- Renal abnormalities
- Facial features (prominent forehead, deep-set eyes, small pointed chin)
- Failure to thrive
- Developmental delay
Treatment Options
Ursodeoxycholic acid (UDCA)
MODERATELY EFFECTIVECholestyramine
MODERATELY EFFECTIVERifampin
MODERATELY EFFECTIVENutritional support (high-calorie diet, fat-soluble vitamin supplementation)
HIGHLY EFFECTIVEPartial external biliary diversion (PEBD)
MODERATELY EFFECTIVELiver transplantation
HIGHLY EFFECTIVEMaralixibat
HIGHLY EFFECTIVE Approved 2021Diagnosis
- Clinical evaluation
- Liver biopsy
- Genetic testing (JAG1 and NOTCH2 genes)
- Echocardiogram (heart ultrasound)
- Abdominal ultrasound
- Ophthalmologic examination
- Skeletal X-rays
History
Alagille syndrome was first described by Daniel Alagille in 1969, who characterized the association of cholestasis, heart disease, and skeletal abnormalities in affected individuals. The genetic basis of the disease was later identified in the 1990s with the discovery of mutations in the JAG1 gene.
Recent Breakthroughs
FDA Approves Maralixibat for Cholestatic Pruritus in Alagille Syndrome
The FDA approved maralixibat, an ileal bile acid transporter (IBAT) inhibitor, for the treatment of cholestatic pruritus in patients with Alagille syndrome aged 1 year and older. This provides a new therapeutic option for managing the debilitating itch associated with ALGS.
Gene Therapy Approaches Showing Promise in Preclinical Studies
Research into gene therapy for Alagille syndrome is ongoing, with preclinical studies showing promising results in animal models. These approaches aim to correct the underlying genetic defect in JAG1 or NOTCH2, potentially offering a curative therapy in the future.