Safety Study of an Adeno-associated Virus Vector for Gene Therapy of Leber's Hereditary Optic Neuropathy

Inclusion Criteria:

1. Age 15 or older;

2. Patients with LHON and the G11778A mitochondrial DNA mutation. A previous CLIA
certified genetic lab result showing the LHON G11778A mutation will be accepted for
inclusion;

3. Ability to perform tests of visual and retinal function;

4. Ability to comply with research procedures;

5. Able and willing to provide informed consent before undergoing any study related
procedures.

6. Good general health as based on the investigator's assessment of the history, physical
examination and laboratory testing performed at the baseline examination.

Exclusion Criteria:

1. Unwilling or unable to give consent,

2. Unable or unlikely to return for scheduled protocol visits

3. Pregnant or nursing women or unwillingness for subject with childbearing potential to
use contraception during the first year of the study.

4. Optic disc drusen on exam or in previous history.

5. Ocular diseases or visual dysfunction conditions other than refractive error (e.g.
amblyopia, glaucoma, etc.) in the eye selected for the injection.

6. Previous eye surgery in the eye selected for injection.

7. Aspartate transaminase (AST)/alanine transaminase (ALT) >5.0 x upper limit of normal
(ULN); Total bilirubin >3 x ULN; Hemoglobin < 8 g/dL; neutrophil count <1.0 x 109/L;
or platelet count < 50 x 109/L

a) Any laboratory screening test that meets the abnormality criteria stated above can
be repeated once between Baseline one to Baseline 2.

8. Type I diabetes or the presence of diabetic retinopathy

9. History of neurodegenerative conditions (e.g. multiple sclerosis, neuromyelitis
optica, Parkinson disease)

10. History of autoimmune conditions (e.g. systemic lupus erythematosus)

11. History of systemic diseases having ocular manifestations likely to confound
assessment of study results.

12. History of cancer within five years other than localized basal or squamous cell
carcinoma not near the orbital area. Patients with a prior history of cancer will need
documentation from their cancer specialist that the cancer was cured at least 5 years
before study entry.

13. Allergy to pupil dilating drops or narrow angles precluding safe dilation.

14. No Light Perception (NLP) vision in either eye.