Isolated ectopia lentis

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

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.

Vision problems are common in people with isolated ectopia lentis. These problems often include nearsightedness (myopia) and double vision (diplopia). The lens or the structure that covers the front of the eye (the cornea) can have an irregular curvature, which causes blurred vision (astigmatism). Affected individuals may also develop clouding of the lenses (cataracts) or increased pressure in the eyes (glaucoma) at an earlier age than other adults. A small number of people with isolated ectopia lentis experience tearing in the lining at the back of the eye (retinal detachment), which can lead to further vision problems and blindness.

In individuals with isolated ectopia lentis, each eye can be affected differently. In addition, the eye problems vary among affected individuals, even those within the same family.

Ectopia lentis is classified as isolated when it occurs without signs and symptoms that affect other body systems. Ectopia lentis can also be classified as syndromic when it is part of a syndrome that affects multiple parts of the body. Ectopia lentis is a common feature of genetic syndromes such as Marfan syndrome and Weill-Marchesani syndrome.

Ectopia lentis can also occur in individuals who experience injury or trauma to the head or eye. Traumatic ectopia lentis is not genetic, can occur at any age, and is the most common cause of ectopia lentis.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

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.

Pathogenic variants in the FBN1 or ADAMTSL4 gene cause cells to make a version of the protein that does not function properly. This can decrease the number of microfibrils or result in the formation of altered microfibrils. Without enough functional microfibrils to form zonular fibers, the lens becomes ectopic. The ectopic lens cannot focus light correctly, contributing to the vision problems that are common in people with isolated ectopia lentis.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

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.

When isolated ectopia lentis is caused by mutations in the ADAMTSL4 gene, it is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell must have a variant to cause the disorder. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

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.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Ectopia lentis · Very frequent (99-80%)

Dislocation or malposition of the crystalline lens of the eye. A partial displacement (or dislocation) of the lens is described as a subluxation of the lens, while a complete displacement is termed luxation of the lens. A complete displacement occurs if the lens is completely outside the patellar fossa of the lens, either in the anterior chamber, in the vitreous, or directly on the retina. If the lens is partially displaced but still contained within the lens space, then it is termed subluxation.

Joint stiffness · Very frequent (99-80%)

Joint stiffness is a perceived sensation of tightness in a joint or joints when attempting to move them after a period of inactivity. Joint stiffness typically subsides over time.

Cognitive impairment · Frequent (79-30%)

Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering.

Malar flattening · Frequent (79-30%)

Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation.

Mandibular prognathia · Frequent (79-30%)

Abnormal prominence of the chin related to increased length of the mandible.

Amblyopia · Occasional (29-5%)

Reduced visual acuity that is uncorrectable by lenses in the absence of detectable anatomic defects in the eye or visual pathways.

Cataract · Occasional (29-5%)

A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.

Ectopia pupillae · Occasional (29-5%)

A malposition of the pupil owing to a developmental defect of the iris.

Other findings in the same source

From: Orphanet

Additional reported features include Hypertension (Occasional (29-5%)); Nystagmus (Occasional (29-5%)); Visual impairment (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Isolated ectopia lentis is Ophthalmology, with a ophthalmologist as the relevant type of clinician. Ophthalmologist; paediatric services for children as appropriate.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which part of the eye or visual pathway is affected?
• What change in vision requires immediate contact with the eye service?
• What are the aims and alternatives of any proposed eye treatment?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Isolated ectopia lentis. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.