Some patients with achromatopsia, an inherited disorder characterized by partial or complete
loss of color vision, carry mutations in ATF6. ATF6 is a gene that is responsible for coding
a protein that acts in response to endoplasmic reticulum (ER) stress. When the ATF6 protein
is mutated, retinal function decreases, contributing to color blindness. The study aims to
investigate whether an already FDA-approved drug, glycerol phenylbutyrate (PBA), can improve
retinal function inpatients with achromatopsia caused by ATF6 mutations. Patients will be
instructed to take three doses of PBA per day at equally divided time intervals and rounded
up to the nearest 0.5 mL. The total dose of PBA will be 4.5 to 11.2 mL/m2/day (5 to 12.4
g/m2/day) and will not exceed 17.5 mL/day (19 g/day). Their condition will be monitored over
the course of a minimum of 3 clinic visits that will consist of a number of retinal function
tests, fundus examinations, and imaging procedures. Findings from the study could elucidate
the potential for PBA to serve as a treatment for patients with ATF6-mediated a chromatopsia.