University of Alabama at Birmingham Aug 29 2025 Retinitis pigmentosa retinal degeneration is caused by a family of hereditary mutations in nearly 100 genes that slowly lead to blindness over years or decades. One of those genes encodes the enzyme DHDDS, part of the pathway that glycosylates proteins in higher cells. Retinitis pigmentosa from DHDDS mutations is called RP59. This is a recessive genetic disease, meaning mutations must be present on both copies of the DHDDS gene to cause disease.