PEDBASE.org - The Pediatric Database - Detailed information of GILBERT SYNDROME

GILBERT SYNDROME

DEFINTION:

A benign disorder of bilirubin metabolism characterized by persistent, unconjugated hyperbilirubinemia and intermittent jaundice.

EPIDEMIOLOGY:

incidence: 6/100 (?)
age of onset:
- newborn (first 4 weeks of life)
risk factors:
- familial - autosomal dominant with variable expression
  - chrom.#: ?2
  - gene: ?
- M > F

PATHOGENESIS:

1. Background

UDP-glucuronosyltransferase is an enzyme which conjugates bilirubin in the liver
there are a number of conditions which affect UDP-glucuronosyl-transferase activity resulting in an unconjugated hyperbilirubinemia:

1. Genetic

1. Crigler-Najjar Syndrome-Type I

severe inherited deficiency of enzyme activity

2. Gilbert Syndrome (Crigler-Najjar Syndrome-Type II)

mild-moderate inherited deficiency of enzyme activity

2. Acquired

1. Lucey-Driscoll Syndrome

an inhibitor of enzyme activity is acquired from the mother's serum

2. Breast Milk Jaundice

an inhibitor of enzyme activity is acquired from the mother's milk

2. Genetic Defect

genetic defect -> reduced hepatic UDP-glucuronosyltransferase activity -> unconjugated hyperbilirubinemia -> intermittent jaundice

CLINICAL FEATURES:

1. Gastrointestinal Manifestations

intermittent jaundice
no risk of kernicterus

INVESTIGATIONS:

1. Serum

unconjugated hyperbilirubinemia
normal AST, ALT, alkaline phosphatase, bile salts
no evidence of hemolysis
exaggerated hyperbilirubinemic response to:
- caloric deprivation
- IV nicotinic acid administration

2. Biopsy

1. Liver

normal on light microscopy
hypertrophy of the endoplasmic reticulum in 50% of patients on electron microscopy

MANAGEMENT:

1. For Hyperbilirubinemia

phototherapy
phenobarbital
- induces UDP-glucouronosyltransferase activity
- 5 mg/kg/day po

2. Prognosis

benign condition with no risk of kernicterus

Pediatric Database - GILBERT SYNDROME

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