Disease at a Glance

Gilbert syndrome is a mild liver disorder that impairs the body's ability to process bilirubin, a substance made when old red blood cells are broken down. This leads to fluctuating levels of bilirubin in the blood, sometimes causing levels to be high (hyperbilirubinemia). Most people with Gilbert syndrome do not have symptoms or have mild jaundice. In some cases, jaundice is triggered or made worse by stress, exercise, fasting, dehydration, drinking alcohol, or illness. Some people with Gilbert syndrome have reported other symptoms such as fatigue, weakness, nausea, or diarrhea. There has not been evidence these other symptoms are caused by hypebilirubinemia, and the cause of these symptoms currently is unclear. People with Gilbert syndrome may also have more side effects from certain drugs such as irinotecan. Gilbert syndrome is caused by genetic changes in the UGT1A1 gene and inheritance is autosomal recessive. Genetic changes in this gene cause reduced levels of a liver enzyme needed to eliminate bilirubin from the body, causing bilirubin to accumulate. People with Gilbert syndrome have about one third of the normal enzyme activity, which usually is enough to prevent symptoms from developing. Of note, genetic changes in the UGT1A1 gene can alternatively cause other disorders, such as Crigler-Najjar syndrome. There are two forms: Crigler-Najjar syndrome type 1 (CN-1) and Crigler-Najjar syndrome type 2 (CN-2). In both types, jaundice is persistent and more severe than in Gilbert syndrome, with CN-1 causing potentially severe symptoms. Sometimes it can be hard to distinguish between Gilbert syndrome and CN-2 because of considerable overlap in measured bilirubin levels. Genetic testing to identify the specific genetic change present is sometimes needed for the correct diagnosis.
Estimated Number of People with this Disease

This section is currently in development.

What Information Does GARD Have For This Disease?

Many rare diseases have limited information. Currently GARD is able to provide the following information for this disease:

*Data may be currently unavailable to GARD at this time.
When do symptoms of this disease begin?
This section is currently in development. 


This section is currently in development. We recommend speaking with a doctor to learn more about this disease. 


This section is currently in development. 

Next Steps

Talking with the Medical Team

Good communication between the patient, family, and medical team can lead to an accurate diagnosis. In addition, health care decisions can be made together which improves the patient’s well-being and quality of life.

Describing Symptoms

Describe details about the symptoms. Because there may be many different causes for a single symptom, it is best not to make a conclusion about the diagnosis. The detailed descriptions help the medical provider determine the correct diagnosis.

To help describe a symptom:

  • Use a smartphone or a notebook to record each symptom before the appointment
  • Describe each symptom by answering the following questions:
    • When did the symptom start?
    • How often does it happen?
    • Does anything make it better or worse?
  • Tell the medical team whether any symptoms affect daily activities

Preparing for the First Visit

Working with a medical team to find a diagnosis can be a long process that will require more than one appointment. Make better health decisions by being prepared for the first visit with each member of the medical team.

    Make informed decisions about health care: 
    • Prepare a list of questions and concerns before the appointment
    • List the most important questions first, not all questions may be answered in the first visit
    • Ask questions about symptoms, possible diagnoses, tests, and treatment options
    For future appointments:
    • Discuss what was not addressed at the last visit
    • Discuss changes in the quality of life for the patient, family, and caregivers
    • Discuss health goals and other issues in the patient’s and family’s life that may affect the health care decisions
    Take notes during the appointments to help remember what was discussed.

    Last Updated: Nov. 8, 2021