Gilbert's syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at June 26, 2016
StartGilbert's syndrome

There are several liver conditions that are associated with abnormal production of enzymes. Gilbert's syndrome (GS) which is also known as Gilbert syndrome, Gilbert–Meulengracht syndrome, constitutional hepatic dysfunction, and familial nonhemolytic jaundice is one such condition. It is mostly harmless and often asymptomatic.


Definition & Facts

Gilbert's syndrome is a genetic disorder and liver condition in which the abnormal production of enzymes affects the function and the processing of bilirubin resulting in the mild elevation of bilirubin, which is called hyperbilirubinemia. Bilirubin is a chemical that is produced after the breaking down of hemoglobin from red blood cells; hyperbilirubinemia is when the level of bilirubin is abnormally high.

Hyperbilirubinemia is caused by hemolysis, Rotor syndrome, or Gilbert's Syndrome, which results in jaundice in which the skin pigment becomes yellowish. Jaundice is commonly associated with liver diseases such as hepatitis and liver cancer.

Symptoms & Complaints

Symptoms and complaints may vary from one patient to another depending on the severity. 30% of people with Gilbert's syndrome don't experience symptoms at all. Aside from jaundice, researchers have not yet been able to confirm consistent symptoms associated with the elevated level of bilirubin.

The most common symptom of GS is jaundice with which there is noticeable discoloration of skin, usually yellowish. The whites of the eyes also become yellowish. Some patients complain of feeling tired easily or fatigue. Anxiety and loss of concentration are other symptoms people with GS have reported.

Meanwhile, there are also complaints such as itching, unexplained weight loss, abdominal pain, and nausea. Diarrhea is also one symptom that may be present among people with GS. Such symptoms may be caused indirectly by several different factors. On the other hand, gallstones may either be a symptom or cause depending on the patient, but this is also another common complaint by people with GS.

Cardiovascular diseases can arise among patients with GS. Nevertheless, the symptoms of Gilbert syndrome are mostly harmless, and jaundice is the primary and the most common symptom.


Gilbert's syndrome is a hereditary condition that can be passed on from parents to children. It is caused by inheriting abnormal genes: primarily a genetic mutation of the UDP-glucuronosyltransferase gene (UGT1A1). Not everyone who inherits this mutation, however, develops Gilbert's syndrome.

The UGT1A1 gene is responsible for making the enzyme (bilirubin-UGT enzyme) that breaks down bilirubin. The enzyme performs a process called glucuronidation which renders bilirubin dissolvable and thereby removable from the body. Because the gene that makes this enzyme performing this process is faulty among people with Gilbert's sydrome, bilirubin proliferates.

Although many people have one copy of this abnormal gene, they will typically not pass it down to their children. GS will most likely be passed on when two people have the same copy of this abnormal gene. Still, there is no guarantee that two people with the same copy of this gene will automatically pass on GS.

For those with Gilbert's syndrome, episodes of bilirubin elevation may be triggered by lack of sleep, strenuous exercise, psychological stress, menstruation, dehydration, low-calorie diet, and illnesses such as common cold and flu.

Diagnosis & Tests

GS can easily be diagnosed through a blood test. Since bilirubin is a chemical that is produced from the breaking down of hemoglobin, bilirubin is present in the blood. Through a blood test, its elevated level can be detected. When the blood test finds and confirms its elevation, it doesn't necessarily confirm that the patient has Gilbert's syndrome.

Liver function tests are also required in diagnosis. A damaged liver may cause elevation of bilirubin and jaundice even without the presence of GS. However, a liver test along with a blood test can confirm the presence of GS. If the blood test confirms the abnormal elevation of bilirubin while the liver test suggests that the liver works normally, then the patient may be diagnosed with Gilbert's syndrome.

Another type of test that can diagnose GS in a patient is a genetic test. These may be necessary to detect the mutations in the genes that cause this condition. Blood tests, liver tests, and genetic tests can all be used in combination in diagnosing whether or not a patient has Gilbert's syndrome.

Treatment & Therapy

Gilbert's syndrome typically does not require treatment because episodes of hyperbilirubinemia are short-lived and long-term effects are minimal. Still, symptoms may be reduced by addressing the abnormality of production of enzymes and the elevation of bilirubin. Some enzyme inducers like phenobarbital may reduce the levels of bilirubin.

Nutrition and changes to a person's diet may play a role in reducing symptoms of Gilbert's syndrome though some medical professionals state that diet and lifestyle have no effect. Some argue that a proper diet plan may reduce reported symptoms like fatigue and difficulty concentrating.

People with Gilbert's syndrome may have to be careful when it comes to taking medications. Medications for HIV, high cholesterol, and chemotherapy may need to be avoided.

Prevention & Prophylaxis

Because some people with GS don't necessarily have high levels of bilirubin all the time, it is important to know what triggers the elevation of bilirubin aside from abnormal production of enzymes in order to prevent episodes of hyperbilirubinemia.

Stress is a primary factor that triggers bilirubin elevation. Managing stress can prevent some GS symptoms to occur. Fasting and low-calorie diet may also be avoided to prevent episodes.