Clinical Evaluation of Patients With X-linked Retinoschisis

The objective of the study is to evaluate subjects with XLRS in a clinical setting and gather
data on disease progression. The data from this study will enhance the understanding of the
natural history of this rare disease and will facilitate appropriately powered safety studies
in a future gene therapy trial in humans.

Inclusion Criteria:

Main Study:

- Clinical diagnosis consistent with XLRS

- Documented disease causing RS1 mutation

- 7 years of age or older

- Able to provide informed consent/assent

- Male

CAI sub-study:

• Presence of maculoschisis

Exclusion Criteria:

Main Study:

• Other eye diseases that might affect the results (e.g. history of retinal detachment,
glaucoma, cataracts that prohibit imaging, or any other eye pathology that in the opinion
of the investigator would preclude enrollment)

CAI Sub-study:

Exclusion Criteria

- Already being treated with CAIs

- Previous documented failure to respond to CAI treatment

Any drug-specific contraindication/precaution listed below (from www.micromedex.com):

Topical Eye Drop Dorzolamide Hydrochloride

Contraindications:

• hypersensitivity to dorzolamide products, including sulfa allergies

Precautions:

- dorzolamide is a sulfonamide that is absorbed systemically, sulfonamide
hypersensitivity reactions may occur

- angle-closure glaucoma

- concomitant use of oral carbonic-anhydrase inhibitors

- conjunctivitis and lid reactions reported with chronic administration

- moderate to severe renal (CrCl less than 30 mL/min) or hepatic insufficiency

- ocular infection or inflammation

- recent ocular surgery

Topical Eye Drop Brinzolamide

Contraindications:

• hypersensitivity to any component of the product, including sulfa allergies

Precautions:

- concomitant use of oral carbonic anhydrase inhibitors is not recommended

- contact lens use; remove contact lenses prior to administration, allow 15 minutes
before reinsertion

- hypersensitivity to sulfonamides; severe reaction may occur; discontinue if signs or
symptoms appear

- low corneal endothelial cell counts; increased risk of corneal edema

- renal impairment, severe (CrCl less than 30 mL/min); use not recommended