Inclusion Criteria:

• Stage 1 and Stage 2 FAP patients with the following:
  • NIS score within protocol criteria
  • Documented transthyretin variant by genotyping
  • Documented amyloid deposit by biopsy
• Females of child-bearing potential must use appropriate contraception and must be non-pregnant and non-lactating. Males engaged in relations of child-bearing potential must use appropriate contraception

Exclusion Criteria:

• Low Retinol level at screen
• Karnofsky performance status ≤ 50
• Poor Renal function
• Known type 1 or type 2 diabetes mellitus
• Known monoclonal gammopathy of undetermined significance or multiple myeloma
• Other causes of sensorimotor or autonomic neuropathy (e.g., autoimmune disease)
• If previously treated with Vyndaqel®, must have discontinued treatment for 2 weeks prior to Study Day 1. If previously treated with Diflunisal, must have discontinued treatment for 3 days prior to Study Day 1
• Previous treatment with any oligonucleotide or siRNA within 12 months of screening
• Prior liver transplant or anticipated liver transplant within 1 yr of screening
• New York Heart Association (NYHA) functional classification of ≥ 3
• Acute Coronary Syndrome or major surgery within 3 months of screening
• Known Primary or Leptomeningeal Amyloidosis
• Anticipated survival less than 2 years
• Have any other conditions in the opinion of the investigator which could interfere with the patient participating in or completing the study