Schnyder crystalline corneal dystrophy (SCD) is a rare form of human corneal dystrophy

Corneal dystrophy (human)

Human corneal dystrophy is a group of disorders, characterised by a noninflammatory, inherited, bilateral opacity of the transparent front part of the human eye called the cornea...

. It is caused by heterozygous mutations in UBIAD1

UBIAD1

UbiA prenyltransferase domain-containing protein 1 also known as transitional epithelial response protein 1 is a protein that in humans is encoded by the UBIAD1 gene....

 gene. Cells in the cornea accumulate cholesterol and phosopholipid deposits leading to the opacity, in severe cases requiring corneal transplants. Abnormal cholesterol

Cholesterol

Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

 metabolism has been noted in other cell types of affected patients (skin fibroblast

Fibroblast

A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework for animal tissues, and plays a critical role in wound healing...

s) suggesting that this may be a systemic disorder with clinical manifestations limited to the cornea

Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...

.

Alternative names

• Crystalline stromal dystrophy
• Schnyder crystalline dystrophy sine crystals
• Hereditary crystalline stromal dystrophy of Schnyder
• Schnyder's crystalline corneal dystrophy