Study of Subretinally Injected ATSN-101 Administered in Patients With Leber Congenital Amaurosis Caused by Biallelic Mutations in GUCY2D

Inclusion criteria : * Male or female participant with clinical diagnosis of Leber congenital amaurosis caused by biallelic mutations in the GUCY2D (retinal guanylate cyclase) gene with all of the following: a) Documented mutations in both alleles of the GUCY2D gene per testing in a CLIA-approved laboratory, b) For Cohort 1-3, best corrected visual acuity (BCVA) of 20/200 or worse in the eye to be injected; subsequent cohorts may include BCVA of 20/80 or worse in the eye to be injected, c) Photoreceptor (outer nuclear) layer structure identifiable on an optical coherence tomography (OCT) scan across the central retina. * Age ≥18 years for Cohorts 1 through 4, and age ≥ 6 years and \<18 years for Cohort 5. * Male and female participants must follow the contraception requirements of the trial. * Participants must agree to not donate blood, organs, tissues, cells or sperm for at least three months following ATSN-101 administration. Exclusion criteria: * Complicating systemic diseases (such as medical conditions causing immunosuppression) that would preclude the gene transfer, ocular surgery or planned study procedures. * History of human immunodeficiency virus (HIV) infection. * Pre-existing eye conditions in the study eye that would preclude the planned surgery or interfere with the assessment and interpretation of study endpoints: for example, glaucoma or optic neuropathy that has resulted in significant visual loss, corneal or lenticular abnormalities or opacities that wou…