This open-label, single-dose, parallel-group study will investigate the pharmacokinetics and safety of RO4917838 in healthy and renal impaired subjects. Subjects will receive a single dose of RO4917838.

Inclusion Criteria:

General criteria

• Body mass index (BMI) between 18 and 32 kg/m2

Criteria applying to renal impaired subjects

• Adult subjects, 18-65 years of age
• Part 1: Subjects with end stage renal disease (ESRD), not on dialysis
• Part 2: Subjects with severe, moderate or mild renal impairment
• Stable renal function

Criteria applying to healthy subjects

• Adult subjects, 18-70 years of age

Exclusion Criteria:

General criteria

• Any condition or disease (other than renal impairment for the renal impaired subjects only) that would render the subject unsuitable for the study, or would place the subject at undue risk
• Any condition which could relapse during or immediately after the study
• History of alcohol or drug abuse

Criteria applying to renal impaired subjects

• Evidence of unstable clinically significant disease other than renal impairment
• Clinically significant liver disease
• Any other major illness (with the exception of renal impairment) within 4 weeks prior to study start

Criteria applying to healthy subjects

• History of any clinically significant disease (e.g., cardiovascular, hepatic, renal, respiratory, gastrointestinal, endocrine, immunologic disease)