Evaluating the efficacity of a new device phototherapy by comparing it with conventional phototherapy. Jaundice occurs in many newborns, and is, in most cases benign, However, owing to the potential neurotoxicity of unconjugated bilirubin, newborns must be monitored to identify those who might develop severe hyperbilirubinemia an, in rare cases, acute bilirubin encephalopathy or kernicterus. Treatment of jaundice in newborn relies on phototherapy, exposing their skin to light of a specific wavelength . Fluorescent tubes or halogen lamps have been used as light sources for phototherapy for many years. Light-emitting diodes (LEDs) are more recent sources which are power efficient, have a longer life and are portable with low heat production. Several technologies and devices are developed using LEDs and specially a compact system.

Crigler-Najjar (CN) syndrome is a congenital inborn error of hepatic bilirubin metabolism caused by the deficiency of bilirubin uridinediphosphate glucuronosyltransferase activity CN patients are at permanent risk of life-threatening bilirubin encephalopathy (kernicterus). Treatment of CN disease relies on daily prolonged phototherapy (10-12 h/day). To date, liver transplantation is the only curative treatment available. To date, no phototherapy device exists for teenagers and adults. CN patients use homemade systems or add several neonatal systems together to reach a better efficacy.

A new device has been designed by weaving optical fibers into a sheet connected to LEDs. This new technology, marketed by several manufacturers of phototherapy devices, is used in pediatric wards for treating jaundiced newborns. A prototype of 80× 100cm was thus developed, which combines numerous advantages : important surface of treatment, easy use and transportation, user-friendliness.

Before going to a therapeutic trial for assessing the benefits of this new device in ambulatory current practice, it is essential to make sure of both its feasibility and efficiency on the control of bilirubinemia, under medical supervision.

Hypothesis: the new phototherapy sheet is as effective as, and better tolerated than the usual devices used in CN patients.

Inclusion Criteria:

• genetic diagnosis of Crigler Najjar disease
• child whose height is between 60cm and 100cm
• patients with follow-up in reference center,

Exclusion Criteria:

• opposition of parents
• no social security insurance