Stargardt's disease
Encyclopedia
Stargardt disease, or fundus flavimaculatus, is an inherited
juvenile macular degeneration
that causes progressive vision loss
usually to the point of legal blindness. The progression usually starts between the ages of six and twelve years old and plateaus shortly after rapid reduction in visual acuity.
The classification "STGD2" is no longer used.
Stargardt disease is the most common form of inherited juvenile macular degeneration.
Some patients are able to drive. Many patients use magnifiers to help them see, and wear sunglasses to slow the development.
cycle. The ATP-binding cassette transporter is defective and leads to a build up of a toxic metabolite lipofuscin
.
There are no clinical trials to provide evidence for ways in which sufferers can slow the progression of the disease. Therefore the advice provided is based on theoretical models of the disease, and includes avoiding bright sun light where possible, and wearing a broad brimmed hat and sunglasses where appropriate.
Currently undergoing trials, AREDS2 is a supplement containing lutein and zeaxanthin thought to slow progression of the disease. Different from AREDS, AREDS2 contains no vitamin A, which Stargardt's patients should avoid.
, an ophthalmologist in Berlin
.
In 1997, it was discovered that mutations in the gene cause Stargardt. The mutations cause the production of a dysfunctional protein that cannot perform energy transport to and from photoreceptor cells in the retina. The photoreceptor cells then degenerate, causing vision loss.
, in June 2006, teased a reporter named Peter Wallsten
who was wearing sunglasses due to Stargardt. The reporter later explained that the President had no way of knowing, and that he was not offended.
Another notable case is US distance runner Marla Runyan
, who, in 2000, became the first legally blind athlete to make the US Olympic team. Runyan, who had previously won seven Paralympic medals, finished eighth in the 1,500 meter finals, the top finish by an American.
Also, in September 2008, at the Beijing Paralympics games, Jason Smyth, representing Ireland, won 2 Gold medals, in the 100m and 200m, with Paralympic world record times. He also became the first Paralympian to compete in the European Championships, in 2010, in Barcelona.
In February 2010, Canadian Paralympic cross-country skier Brian McKeever
was named to the Canadian Olympic team. The seven-time Paralympic medal winner would have been the first winter athlete to compete in both the Paralympic and Olympic Games. However, on 27 February, days before the end of the Olympics, McKeever was omitted from the team when Canada chose four other athletes to replace him, who historically have better times than McKeever.
Heredity
Heredity is the passing of traits to offspring . This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve...
juvenile macular degeneration
Macular degeneration
Age-related macular degeneration is a medical condition which usually affects older adults and results in a loss of vision in the center of the visual field because of damage to the retina. It occurs in “dry” and “wet” forms. It is a major cause of blindness and visual impairment in older adults...
that causes progressive vision loss
Vision loss
Vision loss or visual loss is the absence of vision where it existed before, which can happen either acutely or chronically .-Ranges of vision loss:...
usually to the point of legal blindness. The progression usually starts between the ages of six and twelve years old and plateaus shortly after rapid reduction in visual acuity.
Genetics
It can be associated with several different genes:- STGD1: The most common form of Stargardt disease is the recessiveRecessiveIn genetics, the term "recessive gene" refers to an allele that causes a phenotype that is only seen in a homozygous genotype and never in a heterozygous genotype. Every person has two copies of every gene on autosomal chromosomes, one from mother and one from father...
form caused by mutations in the ABCA4ABCA4ATP-binding cassette, sub-family A , member 4, also known as ABCA4 or ABCR, is a protein which in humans is encoded by the ABCA4 gene....
gene. It can also be associated with CNGB3.
- STGD3: There is also a rare dominant form of Stargardt disease caused by mutations in the ELOVL4ELOVL4Elongation of very long chain fatty acids protein 4 is a protein that in humans is encoded by the ELOVL4 gene.-Further reading:...
gene.
- STGD4: Associated with PROM1.
The classification "STGD2" is no longer used.
Stargardt disease is the most common form of inherited juvenile macular degeneration.
Presentation
Those with Stargardt disease are sensitive to glare; overcast days offer some relief. Vision is most noticeably impaired when the macula (center of retina and focus of vision) is damaged, leaving peripheral vision more intact. Symptoms usually appear before age 20. Symptoms include wavy vision, blind spots, blurriness, impaired color vision, and difficulty adapting to dim lighting.Some patients are able to drive. Many patients use magnifiers to help them see, and wear sunglasses to slow the development.
Pathophysiology
The genetic defect is manifest in the visual phototransductionVisual phototransduction
Visual phototransduction is a process by which light is converted into electrical signals in the rod cells, cone cells and photosensitive ganglion cells of the retina of the eye....
cycle. The ATP-binding cassette transporter is defective and leads to a build up of a toxic metabolite lipofuscin
Lipofuscin
Lipofuscin is the name given to finely granular yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion. It is considered one of the aging or "wear-and-tear" pigments, found in the liver, kidney, heart muscle, adrenals, nerve cells, and ganglion cells...
.
Management of Stargardt disease
Some doctors have recommended colored lenses that filter out wavelengths shorter than 600 nm; the light wavelengths that stimulate rod vision.There are no clinical trials to provide evidence for ways in which sufferers can slow the progression of the disease. Therefore the advice provided is based on theoretical models of the disease, and includes avoiding bright sun light where possible, and wearing a broad brimmed hat and sunglasses where appropriate.
Currently undergoing trials, AREDS2 is a supplement containing lutein and zeaxanthin thought to slow progression of the disease. Different from AREDS, AREDS2 contains no vitamin A, which Stargardt's patients should avoid.
History
The disease was discovered in 1909 by Karl StargardtKarl Stargardt
Karl Bruno Stargardt was a German ophthalmologist born in Berlin.In 1899 he earned his doctorate from the University of Kiel, where he later became chief physician at the university eye clinic. Afterwards he worked in the eye clinic at Strasburg, then becoming head of ophthalmology at Bonn...
, an ophthalmologist in Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
.
In 1997, it was discovered that mutations in the gene cause Stargardt. The mutations cause the production of a dysfunctional protein that cannot perform energy transport to and from photoreceptor cells in the retina. The photoreceptor cells then degenerate, causing vision loss.
Stem Cell Therapy
On November 22, 2010, it was announced that Advanced Cell Technology received United States Food and Drug Administration clearance to immediately initiate a Phase I/II multicenter clinical trial using retinal cells derived from human embryonic stem cells (hESCs) to treat patients with Stargardt’s Macular Dystrophy. This is the first ever human trials of this nature as an approach to treat Stargardt's Macular Dystrophy.Notable cases
George W. BushGeorge W. Bush
George Walker Bush is an American politician who served as the 43rd President of the United States, from 2001 to 2009. Before that, he was the 46th Governor of Texas, having served from 1995 to 2000....
, in June 2006, teased a reporter named Peter Wallsten
Peter Wallsten
Peter Wallsten is a reporter for the Wall Street Journal who covers national politics. Wallsten joined the Journal in October 2009 from the Los Angeles Times, where he authored, with Tom Hamburger, One Party Country: The Republican Plan for Dominance in the 21st Century.A graduate of the...
who was wearing sunglasses due to Stargardt. The reporter later explained that the President had no way of knowing, and that he was not offended.
Another notable case is US distance runner Marla Runyan
Marla Runyan
Marla Runyan , is an American track and field athlete, road runner and marathon runner who is legally blind. She is a three-time national champion in the women's 5000 metres.Runyan was born in Santa Maria, California...
, who, in 2000, became the first legally blind athlete to make the US Olympic team. Runyan, who had previously won seven Paralympic medals, finished eighth in the 1,500 meter finals, the top finish by an American.
Also, in September 2008, at the Beijing Paralympics games, Jason Smyth, representing Ireland, won 2 Gold medals, in the 100m and 200m, with Paralympic world record times. He also became the first Paralympian to compete in the European Championships, in 2010, in Barcelona.
In February 2010, Canadian Paralympic cross-country skier Brian McKeever
Brian McKeever
Brian McKeever is a Canadian cross-country skier and biathlete. He began skiing at the age of three and started competing at thirteen. At 19 he began losing his vision due to Stargardt's disease. At the 2002 and 2006 Winter Paralympics he competed in both cross-country skiing and biathlon...
was named to the Canadian Olympic team. The seven-time Paralympic medal winner would have been the first winter athlete to compete in both the Paralympic and Olympic Games. However, on 27 February, days before the end of the Olympics, McKeever was omitted from the team when Canada chose four other athletes to replace him, who historically have better times than McKeever.
External links
- Stargardt Disease - complete description with links to further information
- Rare Disorders: Stargardt's Disease - a very comprehensive article
- Stargardt's Disease - from the American Macular Degeneration Foundation
- Understanding Stargardt's
- Stargardt's Disease - from TheRetinaSource
- New Hope For Regenerating Damaged Human Retina: Sleeping Stem Cells Successfully Awakened