This is an observational prescreening study. Individuals who are eligible for prescreening will undergo testing procedures that may be used to determine eligibility in ACDN-01 clinical trials.

The prescreening process will be used to help determine the initial eligibility and interest of potential participants in ACDN-01 clinical trials by conducting assessments of key eligibility criteria before the clinical trial screening procedures are performed.

Key Inclusion Criteria:

• Presence of mutations in the ABCA4 gene
• ABCA4 retinopathy phenotype (Stargardt disease type 1 or cone-rod dystrophy)

Key Exclusion Criteria:

• The presence of pathogenic or likely pathogenic mutations in other genes known to cause cone-rod dystrophy or Stargardt maculopathy
• Retinal disease other than ABCA4-related retinopathy
• Presence of a medical condition (systemic or ophthalmic), psychiatric condition, including substance abuse disorder, or physical examination or laboratory finding that may in the opinion of the principal investigator and sponsor preclude adherence to the scheduled study visits, safe participation in the study, or affect the results of the study.

Males and females with a diagnosis of ABCA4-related retinopathy will be invited to give informed consent prior to prescreening procedures. After appropriate informed consent/assent has been obtained, potential participants will then undergo the assessments to determine eligibility for ACDN-01 clinical trials.