Isolated ectopia lentis is a condition that affects the eyes, specifically the positioning of the lens. 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 not centrally positioned as it should be but is off-center (displaced). Isolated ectopia lentis usually becomes apparent in childhood. The lens may drift further off-center over time.

Mutations in the FBN1 or ADAMTSL4 gene cause isolated ectopia lentis. These genes provide instructions for making proteins that are necessary for the formation of threadlike filaments called microfibrils. Microfibrils provide support to many tissues, including the lenses of the eyes, which are held in position by these filaments.

The prevalence of isolated ectopia lentis is unknown. In Denmark, an estimated 6.4 per 100,000 individuals have ectopia lentis, but a large proportion of these cases (about 75 percent) are syndromic.

When isolated ectopia lentis is caused by mutations 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 mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.

Published Date: March 01, 2015
Published By: National Institutes of Health