For patient aged 2 years with known mild to moderate hepatic impairment: in the Investigator's opinion the impairment does not jeopardize patient's safety during the study. For patient aged 2 years with known mild to moderate renal impairment: in the Investigator's opinion the impairment should not jeopardize patient's safety during the study. Patient aged < 2 years with known hepatic impairment (any grade), or patient aged 2 years with known severe hepatic impairment. Patient aged < 2 years with known renal impairment (any grade), or patient aged 2 years with known severe renal impairment.