Abstracto

UBIAD1 and pathogenesis of schnyder’s crystalline corneal dystrophy.

Jumin Xie, Qingzhi Wang

Schnyder’s Crystalline Corneal Dystrophy (SCCD), also known as Schnyder’s Corneal Dystrophy (SCD), is a rare autosomal dominant genetic disorder. The occurrence of SCCD is equal in both genders. SCCD is characterized by progressive corneal opacity, owing to aberrant accumulation of cholesterol and phospholipids in the cornea. A serial of SCCD affected families have been reported in the world, since it was first described in 1924. In 2007, the molecular basis of SCCD was illustrated by three different teams, respectively, and linked to UbiA prenyltransferase domain-containing 1 (UBIAD1). UBIAD1 was first named transitional epithelial response gene 1 (TERE1), which was isolated from the bladder mucosa and proved to be a tumor suppressor.

More studies had demonstrated that UBIAD1 was a key enzyme which involved in vitamin K2 and CoQ10 biosynthesis at distinct organelles. Intracellular geranylgeranyl diphosphate (GGpp) molecules triggered the binding of UBIAD1 to 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCR) at Endoplasmic Reticulum (ER) membranes. The mutated UBIAD1 that caused SCCD was not able to bind GGpp, which resulted in the consistent binding of UBIAD1 to HMGCR at ER membranes. The long-term binding of HMGCR at ER membranes led to excess cholesterol biosynthesis and accumulation, finally, SCCD disease in cornea. Though the molecular basis and pathogenesis of SCCD had been clarified by efforts of couples of ophthalmologists and scientists around the world, more studies need to be done to better understand the working mechanism of UBAID1. Our review could guide effective diagnosis and treatment of SCCD for clinicians