Late Onset Stargardt’s Disease

Sana Masroor   by Sana Masroor, M.S., Biochemistry    Last updated on March 4, 2020,

What is Late Onset Stargardt’s Disease?

Late onset Stargardt disease is an age related macular degeneration (AMD) and is associated with missense mutation outside functional domains ABCA4.

Late-onset Stargardt disease involves a typical phenotype of yellow-white flecks and retinal pigment epithelium (RPE) atrophy. Symptoms of atrophy may initially occur in the parafoveal retina and radially expand in size over time.

What are The Symptoms of Late Onset Stargardt’s Disease?

Late onset Stargardt’s disease patients usually encounters with metamorphopsia (a distorted vision in which a grid of straight lines appears wavy and parts of the grid may appear blank) and no visual acuity.

The disease occurs in adults of 40-50 years age. The symptoms may include:

  • blind spots
  • blurred vision
  • sometimes the condition becomes asymptomatic

What Is the Diagnosis of Late Onset Stargardt’s Disease?

Patients with this disease are generally asymptomatic and coincidentally diagnosed during screening tests for other retinal diseases like glaucoma, diabetes, or thyroid problems.

Genetic analysis tests specific for mutation in ABCA4 gene are usually done to diagnose late onset stargardt’s disease.

Biomarkers to identify this disease are crucial. Fundus autofluorescence (FAF) imaging may clearly visualize areas of retinal pigment epithelium (RPE) atrophy which is a frequent feature of late onset stargardt’s disease and change in RPE atrophy over a time.

Fluorescein angiography of RPE hypertrophy typically presents the blockage of fluorescence (except in the areas of atrophy which are hyper fluorescent).

Optical coherence tomography (OCT) of RPE hypertrophy will show both thickening and thinning of retina. The overlying retina becomes thinned and the retinal pigment epithelium can be either thickened or thinned. Beside, the underlying choroid may become typically thinned.

These tests are done for RPE atrophy which is the most common issue found in late onset stargardt’s disease patients.

What is the Treatment of Stargardt’s disease?

In recent years, discovering biomarkers in retinal disease has become a crucial issue for therapeutic trials that aim to test the efficacy of a drug. A surrogate outcome measure adopted by the U.S. Food and Drug Administration is atrophy in late onset Stargardt’s disease.

Research has shown that RPE atrophy can also be used as an outcome measure in late-onset Stargardt. For late-onset Stargardt patients, their adult age makes them ethically more appropriate candidates to participate in clinical trials than patients in minor age.

Although treatment of late onset stargardt’s disease is still unknown but it has proven that RPE atrophy is a frequent characteristic of this disease. The treatment for RPE atrophy can be suggested in cases of late onset Stargardt.

Vitamin A supplements betacarotene is generally suggested in age related macular degeneration patients.

Frequently Asked Questions

Satrgardt’s disease is a genetic eye disorder which causes progressive loss of vision. It is generally caused by mutations in the ABCA4 gene and inherited in an autosomal recessive manner in future generations. Sometimes, it may be caused by mutations in other genes and inherited in an autosomal dominant manner, though it is rare.

The ABCA4 gene provides instructions for making a protein that is found in the retina, a specialized light-sensitive tissue that lines the back of your eye. This gene was first cloned and characterized in 1997 as a gene which causes Stargardt’s disease (an autosomal recessive disease that causes macular degeneration).

Retinal pigment epithelium (RPE) is a pigmented layer that lies outside the neurosensory retina that nourishes the retinal visual cells, and is firmly or closely attached to the underlying choroid and overlying retinal visual cells. It is the post mitotic layer which functions both as a vegetative regulator and selective barrier of the photoreceptor layer, and plays a key role in maintenance.

This disease generally causes vision loss during childhood or adolescence. Although in some forms, vision loss may not be seen until later in adulthood. Stargardt disease is one of the several genetic disorders that cause macular degeneration. It is rare for people to become completely blind with the disease.

Sana Masroor

Sana Masroor is a biochemist and has pursued her Master’s degree in biochemistry from Jamia Millia Islamia University, New Delhi.  She has worked as a Research Trainee in the Special Center for Molecular Medicine, Jawaharlal Nehru University, New Delhi.

Read More Articles by this Author