A Study to Evaluate the Pharmacokinetics, Safety, and Pharmacodynamics of Olpasiran in Participants With Various Degrees of Hepatic Impairment

Inclusion Criteria: * Male or female participants of nonchildbearing potential, between 18 and 75 years of age (inclusive) at the time of Screening. * Body mass index between 18.0 and 40.0 kg/m\^2 (inclusive) at the time of Screening. Participants with Normal Hepatic Function Only: • In good health, determined by no clinically significant findings from medical history, physical examination, 12-lead ECG, vital signs measurements, and clinical laboratory evaluations at Screening and Check-in as assessed by the Investigator (or designee). Participants with Hepatic Impairment Only: • Child-Pugh A (Group 2), B (Group 3), or C (Group 4) classification defined by both Screening (to determine participant group) and Check-in (to confirm participant group prior to dosing) clinical laboratory values and physical examination findings. Exclusion Criteria: * History of significant hypersensitivity, intolerance, or allergy to any drug compound, food, or other substance, unless approved by the Investigator (or designee). * Estimated glomerular filtration rate \< 60 mL/min/1.73m\^2 (Groups 1-3) or \< 50 mL/min/1.73m\^2 (Group 4 only) by Modification of Diet in Renal Disease formula at Screening or Check-in. * Receiving or has received any investigational drug within the 30 days or 5 half-lives (whichever is longer) before receiving olpasiran. * Participants who were previously exposed to olpasiran. * Female participants with a positive pregnancy test at Screening or Check-in. Participants with Normal Hepatic Function Only: * Positive hepatitis panel. Participants whose results are compatible with prior immunization may be included. * Alanine aminotransferase and aspartate aminotransferase elevations \> 3x upper limit of normal at Screening or Check-in. Participants with Hepatic Impairment Only: * Positive for hepatitis B surface antigen. Participants with positive hepatitis B core antibody may be included if hepatitis B surface antigen is negative. Participants with positive hepatitis B surface antibody may be included (consistent with prior vaccination). * Active malignancy of any type. Participants with a history of malignancy that has been eradicated with supporting medical documentation indicating that there is no residual malignancy detected in the past 2 years will be allowed. * Values outside the normal range for liver function tests that are not consistent with their hepatic condition, as determined by the Investigator (or designee).