ELOVL4 gene codes for a protein that is found primarily in the retina.  This protein called ELOVL Fatty Acid Elongase 4, is a member of the ELO protein family and is produced in photoreceptors.  The ELOVL4 protein is also found in the brain and skin, but little is known about its expression in these structures.  Inside photoreceptor cells, this protein is located in a cell structure called the endoplasmic reticulum that is involved in protein production, processing, and transport.  The ELOVL4 protein plays a role in making a group of fats called very long-chain fatty acids.  The protein helps add carbon molecules to long-chain fatty acids, making them very long-chain fatty acids.

Mutations in the ELOVL4 gene create a premature stop signal in the instructions used to make the ELOVL4 protein.  As a result, the protein cannot be retained in the endoplasmic reticulum of photoreceptor cells.  Instead, the ELOVL4 protein forms clumps (aggregates).  These aggregates cannot make very long-chain fatty acids and may interfere with cell functions, ultimately leading to cell death.  Studies in animal models have shown that defective ELOVL4 proteins are unable to prevent water loss from the skin in a desiccating environment leading the animals to dehydrate very quickly and die as a result.  Mutations in this gene are implicated in different diseases, including ISQMR, a syndrome of ichthyosis, spastic quadriplegia and mental retardation, a subtype of spinocerebellar ataxia (SCA34), and a form of macular degeneration known as Stargadt Disease.