UBIAD1 is a human MK-4 biosynthetic enzyme.  It is a human homolog of the E. coli prenyltransferase menA, which is involved in the vitamin K biosynthetic pathway.  UBIAD1 gene provides the instructions to produce a protein involved in cholesterol and phospholipid metabolism.  

Mutations in this gene are associated with Schnyder crystalline corneal dystrophy (SCD).  Most cases reported in the literature were from Western and Asian families.  More than 21 missense mutations in this gene have been described.

Mutation in the UBIAD1 gene causes SCD which is inherited in an autosomal dominant pattern.  UBIAD1 gene is located on the short arm of chromosome 1.  It consists of 2 exons and spans about 12 kb. This gene encodes a protein believed to be involved in the metabolism of cholesterol and phospholipid.