MONDO_0009959 (peroxisome biogenesis disorder type 3B) is a genetic disorder characterized by abnormalities in the breakdown of phytanic acid. It results in accumulation of phytanic acid in the blood, brain and other tissues. Signs and symptoms include retinitis pigmentosa which may lead to blindness, hearing problems and deafness, hypotonia, ataxia, nystagmus, facial deformities, and mental and growth retardation. Also known as: infantile phytanic acid storage disease, peroxisome biogenesis disorder 3B.