Study to Learn About the Safety of Fazirsiran and if it Can Help People With Alpha-1 Antitrypsin Liver Disease With Mild Liver Scarring (Fibrosis)

Inclusion Criteria: * In the opinion of the investigator, the participant is capable of understanding and fully complying with the protocol requirements and adhering to the protocol schedule. * The participant is able to read, understand, and complete the study questionnaires electronically per the investigator's judgment. * The participant signs and dates a written Informed Consent Form (ICF). Any required privacy authorization should also be signed before the initiation of any study procedures. * The participant, of any sex, is aged 18 to 75 years, inclusive. * The participant must have a diagnosis of the protease inhibitor Z mutation (PiZZ) genotype AATD. A diagnosis of PiZZ from source-verifiable medical records is permitted. Otherwise, participants must undergo PiZZ confirmatory testing (genotyping for PiS and PiZ alleles) at screening. PiMZ or PiSZ genotypes are not permitted. * The participant's liver biopsy core samples collected as per protocol requirements. * The participant has evidence of METAVIR stage F1 liver fibrosis, evaluated by a centrally read baseline liver biopsy during the screening period; or confirmed as meeting all the entry criteria by central reading from a previous biopsy conducted within 1 year before the estimated enrollment date using an adequate liver biopsy and slides as defined in the study laboratory manual. * The participant has a pulmonary status that meets the protocol requirements. * It must be confirmed that the participant does not ha…