Isolated ectopia lentis is a condition that affects the positioning of the lens in the eyes. The lens is a clear structure at the front of the eye that helps focus light. In people with isolated ectopia lentis, the lens in one or both eyes is out of place (ectopic) instead of centrally positioned. Isolated ectopia lentis is often present at birth but may become apparent during childhood. The lens may drift further out of place over time.

Changes in the FBN1 or ADAMTSL4 gene cause isolated ectopia lentis. Genetic changes that cause disease are called pathogenic variants. Pathogenic variants in the FBN1 gene are more common among people with isolated ectopia lentis than variants in the ADAMTSL4 gene. These genes provide instructions for making proteins that are necessary for the formation of threadlike filaments called microfibrils. Microfibrils provide support to many tissues. Within the eyes, microfibrils form small bundles called zonular fibers that hold the lenses of the eyes in their central position.

The prevalence of isolated ectopia lentis is unknown. The prevalence of ectopia lentis due to genetic causes, both isolated and syndromic, is estimated to be 6 in 100,000 individuals.

When isolated ectopia lentis is caused by pathogenic variants in the FBN1 gene, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the variant from one affected parent. Other cases result from a new (de novo) variant in the gene that occurs during the formation of reproductive cells (eggs or sperm) in an affected individual's parent or during early embryonic development. These affected individuals typically have no history of the disorder in their family.

Published Date: April 01, 2026
Published By: National Institutes of Health