Joubert Syndrome (JBTS) is a rare disease affecting 1 in every 80-100 thousand live births. It affects the brain, in varying degrees, as well as the eyes, kidneys, and skeleton. Mutations in the ARL3 gene cause JBTS by affecting structures on cells known as cilia. Cilia are antenna-like projections from cells which sense the environment and send signals into cells to ensure normal development and function of organs in the body. ARL3 mutations prevent cilia from working normally and cause problems with brain development, vision and kidney function.