Patients with a history of toxic epidermal necrolysis (TEN) or Stevens-Johnson syndrome are excludedXx_NEWLINE_xXPatients with Down syndromeXx_NEWLINE_xXActive or a history of Tourette�s syndrome or tic disorderXx_NEWLINE_xXNo history of Steven�s Johnson�s syndrome, toxic epidermal necrolysis (TEN)s syndrome, or motor neuropathyXx_NEWLINE_xXPatients with Down syndrome are not eligibleXx_NEWLINE_xXDiagnosis of Down syndrome (Trisomy 21)Xx_NEWLINE_xXPatients must not have known Gilbert�s syndromeXx_NEWLINE_xXNo known Gilbert�s syndrome or known homozygosity for UGAT1A1*28 polymorphismXx_NEWLINE_xXPatients with Down syndromeXx_NEWLINE_xXDown syndromeXx_NEWLINE_xXPatients with down syndrome are excluded from this studyXx_NEWLINE_xX