The purpose of this study is to evaluate the safety, tolerability, pharmacodynamics (PD) and pharmacokinetics (PK) of single ascending doses of ALN-TTRSC04.

Inclusion Criteria:

• Body mass index (BMI) ≥18.0 kg/m^2 and ≤30 kg/m^2 assessed at Screening.

Exclusion Criteria:

• Has an estimated glomerular filtration rate (eGFR) <90 mL/min/1.73m^2 at screening.
• Has alanine aminotransferase (ALT), aspartate aminotransferase (AST) or direct bilirubin above the upper limit of normal (ULN).