Fatty acid elongases are a family of enzymes found in eukaryotes that belong to the transferases. Elongases are presumably localized in the endoplasmic reticulum (see fatty acid synthesis below). They catalyze a condensation in the fatty acid elongation cycle. The fatty acid is extended by one C2 body per cycle (elongation).
Seven fatty acid elongases are known in humans. They are encoded by the ELOVL1-7 genes. Mutations in the ELOVL4 gene are the cause of type 3 Stargardt syndrome, a very rare juvenile macular degeneration.