Other
Symptoms, whether connected or not to GS, have been reported in a subset of those affected: fatigue (feeling tired all the time), difficulty maintaining concentration, unusual patterns of anxiety, loss of appetite, nausea, abdominal pain, loss of weight, itching (with no rash), and others, such as humor change or depression. But scientific studies found no clear pattern of adverse symptoms related to the elevated levels of unconjugated bilirubin in adults. However, other substances glucuronidized by the affected enzymes in those with Gilberts syndrome could theoretically, at their toxic levels, cause these symptoms. Consequently, debate exists about whether GS should be classified as a disease. However, Gilbert syndrome has been linked to an increased risk of gallstones. Cause
Mutations in the UGT1A1 gene lead to Gilbert Syndrome. The gene provides instructions for making the bilirubin uridine diphosphate glucuronosyltransferase (bilirubin-UGT) enzyme, which can be found in the liver cells and responsible for the removal of bilirubin from the body.The bilirubin-UGT enzyme performs a chemical reaction called glucuronidation. Glucuronic acid is transferred to unconjugated bilirubin, which is a yellowish pigment made when your body breaks down old red blood cells, and then being converted to conjugated bilirubin during the reaction. Conjugated bilirubin passes from the liver into the intestines with bile. Its then excreted in stool. People with Gilbert syndrome have approximately 30 percent of normal bilirubin-UGT enzyme function, which contributes to a lower rate of glucuronidation of unconjugated bilirubin. This toxic substance then accumulates in the body, causing mild hyperbilirubinemia.
Differential diagnosis
While Gilbert syndrome is considered harmless, it is clinically important because it may give rise to a concern about a blood or liver condition, which could be more dangerous. However, these conditions have additional indicators:
In GS, unless another disease of the liver is also present, the liver enzymes ALT/SGPT and AST/SGOT, as well as albumin, are within normal ranges. More severe types of glucuronyl transferase disorders such as Crigler–Najjar syndrome (types I and II) are much more severe, with 0–10% UGT1A1 activity, with affected individuals at risk of brain damage in infancy (type I) and teenage years (type II). Hemolysis of any cause can be excluded by a full blood count, haptoglobin, lactate dehydrogenase levels, and the absence of reticulocytosis (elevated reticulocytes in the blood would usually be observed in haemolytic anaemia). Dubin–Johnson syndrome and Rotor syndrome are rarer autosomal recessive disorders characterized by an increase of conjugated bilirubin. Viral hepatitis associated with increase of conjugated bilirubin can be excluded by negative blood samples for antigens specific to the different hepatitis viruses. Cholestasis can be excluded by normal levels of bile acids in plasma, the absence of lactate dehydrogenase, low levels of conjugated bilirubin, and ultrasound scan of the bile ducts. Vitamin B12 deficiency - elevated bilirubin levels (and MCV counts above 90–92) can be associated with a vitamin B12 deficiency. Treatment
Typically no treatment is needed. If jaundice is significant phenobarbital may be used. History
Gilbert syndrome was first described by French gastroenterologist Augustin Nicolas Gilbert and co-workers in 1901.