Hereditary hyperbilirubinemia

Hereditary hyperbilirubinemia refers to a group of genetic conditions in which levels of bilirubin, a byproduct of red blood cell breakdown, are elevated in the blood because of an inherited cause. These conditions result from mutations affecting the liver enzymes that normally process bilirubin, and the resulting elevated levels can cause jaundice, the yellowing of the skin and eyes. They are classified as either conjugated or unconjugated hyperbilirubinemias depending on where in the bilirubin processing pathway the enzyme defect occurs, and their prevalence varies widely by type, with Gilbert syndrome, the most common form, affecting an estimated two to ten percent of the population, while other hereditary hyperbilirubinemias are considerably rarer.