This disease is often referred to as familial nonhemolytic jaundice. It is a hereditary autosomal dominant disorder characterized by recurrent fluctuating elevations in bilirubin secondary to impaired bilirubin metabolism. Often the cause for such fluctuations includes fasting, stress, hyperthyroidism, menstrual periods, and intercurrent illness. The only clinical manifestation is jaundice. Typically, other liver-associated laboratory values are normal. It is felt to be a common disorder, affecting approximately 5% of the population. It appears to be more predominant in males. The underlying pathology is a partial deficiency of glucuronyl transferase.

Diagnosis does not require liver biopsy. A prolonged, mild, unconjugated hyperbilirubinemia in the absence of other abnormalities of liver dysfunction or hemolysis is enough to suggest Gilberts syndrome. The diagnosis is further inferred by a normal-colored urine and a lack of bilirubinuria. Diagnosis is confirmed by performing a 48-hour fast (fewer than 400 calories/day), which will result in a marked exaggeration of the patients hyperbilirubinemia when Gilberts disease is present. Additionally, intravenous administration of nicotin acid will also promote hyperbilirubinemia, but this method of diagnosis is not commonly employed.

Treatment is only symptomatic as the most common complaints are of fatigue and malaise, which may induce anxiety in some patients. Patients with this disorder may expect a normal life span without complications from this disorder.