Retinitis pigmentosa is a group of rare eye diseases that affect the retina. RP causes progressive disfunction of rod photoreceptors with subsequent degeneration of cone photoreceptors and the retinal pigment epithelium, resulting in vision loss. Symptoms start in childhood and most individuals eventually lose the majority of their sight.

Stargardt disease is a genetic eye disease that causes retinal degeneration and vision loss. It is the most common form of inherited macular degeneration, affecting about 30,000 people in the U.S. The progressive vision loss is caused by the degeneration of photoreceptor cells in the central portion of the retina called the macula.

Usher 1B is a genetic disorder characterized by hearing loss, deafness and progressive vision loss.

Parkinson's disease (PD) is a brain disorder that causes unintended or uncontrollable movements, such as shaking, stiffness, and difficulty with balance and coordination. Symptoms usually begin gradually and worsen over time. As the disease progresses, people may have difficulty walking and talking. Distinct genetic drivers cause about 10% to 15% of all Parkinson's.

Friedreich's ataxia is a genetic disease that causes difficulty walking, a loss of sensation in the arms and legs, and impaired speech that worsens over time. Symptoms generally start between 5 and 20 years of age.