A gene that causes severe glaucoma in babies has been identified by scientists at Northwestern and Wisconsin-Madison universities in the United States, paving the way for the development of a drug treatment for this eye disease.
The discovery was described as an “exciting development” by a Greek professor, who believes that it creates hope for babies suffering from the disease. “Especially in our country, congenital glaucoma is one of the main causes of blindness in newborns, especially the firstborn boys, and the prospect of locating the culprit gene during pregnancy and treating congenital glaucoma with special eye drops in infancy is exciting. “, Said Dr. Anastasios-I. Kanellopoulos, Professor of Ophthalmology at New York University, Scientific Director of the Laser Vision Ophthalmological Institute in Athens and President of the International Society for Refractive Surgery (ISRS).
According to the researchers in The Journal of Clinical Investigation, the gene they identified is called TEK and is involved in the development of an eye vessel called the Schlemm canal, which is responsible for draining ocular fluid (aqueous humor) from the front of the eye. . In glaucoma, this vessel may be defective or completely absent, causing the aqueous humor to accumulate and increasing the pressure inside the eye (intraocular pressure), causing damage to the optic nerve leading to progressive vision loss.
The researchers led by Dr. Susan Quaggin, a professor of medicine at Northwestern University’s Feinberg School of Medicine, discovered two years ago that deleting this gene from animal models leads to glaucoma, but so far they do not know if the same gene affects humans. To determine if this is the case, Dr. Quaggin collaborated with Dr. Terri Young, a pediatric ophthalmologist and director of ophthalmology at the University of Wisconsin-Madison, who had identified TEK mutations in some of her patients but was unaware of their significance. “It was more than a coincidence,” she said. Quaggin. “Our meeting led to a collaboration with ophthalmologists and geneticists from around the world who discovered more mutations in this gene in children with primary congenital glaucoma. “It was one of those moments in science when something unique happened.” In total, the researchers identified TEK mutations in 10 unrelated families with primary congenital glaucoma. None of the affected children had mutations in the other genes known to cause glaucoma.
The scientists then proved that TEK mutations disrupt the mechanism necessary for the formation of the Schlemm channel. “Although we know several glaucoma-related genes, TEC is the first we know exactly how it works to cause the disease and therefore may be a new therapeutic target for severe glaucoma and possibly other, more common forms of the disease. “, Stressed Dr. Quaggin.
Researchers have already begun testing a special eye drop that repairs the TEK mechanism to repair the defective blood vessel, while continuing their research to see if this gene also plays a role in adult glaucoma. “Congenital glaucoma does not have early symptoms, because the increase in intraocular pressure does not cause pain or other discomfort,” says Dr. Kanellopoulos. “Because in our country there is no complete ophthalmological examination in infancy (up to 6 months) by an ophthalmic surgeon, as required in most countries of the world, congenital glaucoma is felt by parents and / or pediatrician by the ophthalmologist (it grows too much one or both eyes of the baby) or the whitening of the cornea by the swelling caused by the increased pressure.
Fortunately, there is a highly effective surgery for newborns, called genotomy, that can lead to permanent healing. We hope that the shocking new findings will find a possible application in the classic glaucoma of adults, which is much more common and is a major cause of adult blindness.
General information about childhood glaucoma.
Glaucoma is a group of eye diseases, with the common feature being progressive optic nerve damage. The most common cause of this damage is increased eye pressure (intraocular pressure).
Usually the intraocular pressure is high because the eye produces the aqueous humor it needs to be healthy, but it is unable to drain it adequately. If glaucoma is not diagnosed and treated early, optic nerve damage can lead to total blindness. Although glaucoma is usually a disease of the elderly, it can occur at any age. Childhood glaucoma can be congenital, infantile or juvenile.
The relative manifests shortly after birth (usually within a few days), the infant appears at the age of 1 to 24 months while the juvenile appears after the age of 3 years. Infants and children with glaucoma typically have different symptoms than adult patients. The most common symptoms in congenital and infantile glaucoma are excessive tearing, sensitivity to light, and a swollen, blurred cornea that can make the iris (the colored part of the eye) appear blurred.
However, the tearing accompanied by secretions is usually not caused by glaucoma, but by a congenital obstruction of the nasolacrimal duct (it is the “tube” that connects the eyes to the nose and from which the tears drain). Juvenile glaucoma usually develops without obvious symptoms, as is the case with adult glaucoma. However, patients with juvenile glaucoma often have a family history of the disease and are therefore screened at an early age.
Most cases of pediatric glaucoma have no known etiology and are called primary glaucoma. When they have an external cause or are related to a specific disorder or disease, they are called secondary glaucoma.
Examples of disorders that can cause secondary childhood glaucoma are Axenfeld-Reiger syndrome, aniridia, Sturge-Weber syndrome, neurofibromatosis, chronic steroid use, injury, or previous eye surgery (eg, removal of a child).
Childhood glaucoma is relatively rare. Primary congenital and primary infantile glaucoma are estimated to affect a baby at 10,000 births, with 10% of cases being hereditary.