Clinical Assessment Study in Crigler-Najjar Syndrome

Key Inclusion Criteria:

- Subject has a diagnosis of Crigler-Najjar syndrome resulting from a confirmed mutation
in the UGT1A1 gene

- Subject is aged equal or greater than 1 year of age

- Subject receives daily phototherapy for a minimum of 6 hours within a 24-hour period
(daily illumination time)

Exclusion Criteria:

- Subject is currently participating in an interventional study or has received gene or
cell therapy

- Subject has received a whole liver, partial liver, or hepatocyte transplant; or
subject has a liver transplant scheduled within the planned participation period of
this study

- Subject has significant cholestatic disease, in the opinion of the investigator

- Subject is receiving phenobarbital or other known inducer of UGT1A1 within 30 days of
screening

- Subject has any clinically significant underlying liver disease (other than
Crigler-Najjar syndrome), in the opinion of the investigator

- Subject has a history of, or currently has, a clinically important condition other
than Crigler-Najjar syndrome, in the opinion of the investigator