Final answer:
Familial disorders that cause unconjugated hyperbilirubinemia include Crigler-Najjar syndrome, Gilbert's syndrome, and chronic idiopathic jaundice. These conditions involve genetic enzyme deficiencies that impair the liver's ability to conjugate bilirubin. Pediatric liver diseases such as biliary atresia and alpha-1 antitrypsin deficiency also contribute to this condition.
Step-by-step explanation:
Familial Disorders Causing Unconjugated Hyperbilirubinemia
The familial disorders causing unconjugated hyperbilirubinemia primarily involve genetic defects that impact the liver's ability to process and excrete bilirubin from the bloodstream. One such disorder is Crigler-Najjar syndrome, which is characterized by the absence of the enzyme UDP glucuronyl transferase, necessary for converting bilirubin into its water-soluble form. There are two types of Crigler-Najjar syndrome; Type I is more severe with serum bilirubin levels that can exceed 20 mg/dl, indicating extreme hyperbilirubinemia. Type II is less severe, where the liver can form bilirubin monoglucuronide but cannot further process it due to the absence of the enzyme UDP glucuronyl transferase-II.
Gilbert's syndrome is another genetic disorder that results in decreased UDP-glucuronyl transferase activity, reducing the liver's ability to conjugate bilirubin. This common condition affects approximately 5% of the population.
Other conditions such as chronic idiopathic jaundice also lead to increased levels of unconjugated bilirubin. This autosomal recessive disorder is not only limited to bilirubin but also affects the secretion of conjugated estrogens and other substances.
Additional pediatric liver diseases include biliary atresia, alpha-1 antitrypsin deficiency, alagille syndrome, and progressive familial intrahepatic cholestasis. Each of these can lead to unconjugated hyperbilirubinemia due to various defects in bile secretion and metabolism.