Atypical biliary tract abnormalities found in Alagille syndrome baby
Case report indicates unusual signs should prompt genetic testing
A six-month-old baby with Alagille syndrome showed atypical biliary tract abnormalities, including a narrower main bile duct and a gallbladder with a corkscrew-like shape, according to a case report from Italy.
The biliary tract refers to the system through which bile, a digestive fluid, is produced in the liver, transported through the bile ducts, and stored in the gallbladder, a pear-shaped organ located beneath the liver.
Alagille is marked by a reduced number of bile ducts inside the liver, which causes slowed or stalled bile flow, a condition known as cholestasis. Abnormalities in biliary structures outside the liver, especially involving the gallbladder, are less common.
Some of these uncommon signs warrant testing for Alagille, the researchers wrote.
The case study, “Alagille syndrome with unusual common bile duct hypoplasia and gallbladder dysmorphism: Lesson based on a case report,” was published in Radiology Case Reports.
Gallbladder as Alagille hallmark
Alagille syndrome is a congenital, genetic disorder mainly caused by mutations in the JAG1 gene that result in abnormalities during embryonic development. The disease can lead to abnormalities in several organs and tissues, such as the heart, bones, and kidneys, but the liver is the most commonly affected.
Liver problems in Alagille, commonly marked by cholestasis, are typically caused by intrahepatic bile duct paucity, or a lower number of bile ducts inside the liver. Over time, slowed bile flow results in bile accumulation in the liver, which may cause organ damage and eventually result in the need for a liver transplant.
Researchers at the University of Catania, Italy, described the case of the baby referred to their department due to cholestasis, which can cause symptoms like itching and yellowing of the skin and the whites of the eyes.
Physical examination revealed the child was in “fair general condition” and responded normally to sensory stimuli, the researchers wrote. Blood tests indicated elevated levels of several liver damage markers, including bile acids, bilirubin, and liver enzymes.
Ultrasound and magnetic resonance imaging revealed intrahepatic bile duct paucity, a significant reduction in the diameter of the main bile duct, and a gallbladder with an atypical, corkscrew-like appearance. The main bile duct transports bile from the liver to the gallbladder and from there to the intestines.
The corkscrew shape of the gallbladder may have been due “to the reduction in the caliber of the main bile duct which therefore hinders the emptying of the gallbladder,” the researchers wrote. This gallbladder abnormality had not been previously reported in scientific literature and could be a distinctive hallmark of Alagille, they noted.
Imaging tests also showed that the left kidney was in an abnormal position and that some vertebrae had a “butterfly” appearance, a common bone condition in Alagille, they wrote.
At this point, researchers suspected Alagille syndrome, which was confirmed by genetic testing that revealed the child had JAG1 gene mutations consistent with the disease.
The child was treated with ursodeoxycholic acid, a medication sold under the brand names Urso and Actigall that helps bile move through the bile ducts, for 15 days, until there was a significant decrease in markers of cholestasis and liver damage.
The child was then discharged, with laboratory and ultrasound tests recommended every three months.
“In the absence of information on family history, in our opinion, the [ultrasound] finding of a gallbladder with a ‘corkscrew’ appearance, of a [main bile duct outside the liver] with reduced caliber, associated with high indices of cholestasis, should suggest further investigations with MRI and genetic tests,” the researchers wrote. “Failure to diagnose can expose patients to serious health risks.”
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