ICR | Eye health | Eye diseases with genetic factors

Eye diseases with genetic factors

genetic risk

Eye diseases with a genetic basis are caused by alterations in genetic code that appear throughout life and cause vision problems affecting to a greater or a lesser degree the patient’s quality of life. Due to their genetic nature, most eye diseases with a genetic component are usually inhereted from parents to children, though not all of them manifest the disease.

This pathologies may affect different eye tissues: the macula, the cornea, the optic nerve, etc. Over 60% of child blindness cases are due to diseases with genetically-related factors.

Main genetically-based eye diseases

  • Inhereted retinal disorders: These are different retinal diseases of genetic origin that lead to degeneration of the photoreceptor cells (cones and rods) in most cases. The most common is retinitis pigmentosa, a disease that affects these retinal cells, mainly the rods, which are responsible for peripheral vision and vision in low light conditions. There are currently more than 100 genetic variants known to be causative, which is one of the reasons why there is variability in the form of presentation among patients.

  • Congenital glaucoma, a rare type of glaucoma affecting newborns and small children, that may be hereditary and has a genetic base.
  • Congenital cataract. Cataracts usually appear at advanced ages and consist in the clouding of the crystalline lens, a natural lens in our eyes. Nevertheless, congenital cataracts are already present at birth due to genetic causes. They are usually hereditary and may affect one or both eyes.
  • Inherited strabismus. Eye misalignment may, in some cases, be hereditary. Therefore, in case of family history of strabismus, it is necessary for the child to undergo a comprehensive eye exam.
  • Malformations. Anophthalmia (complete absence of one or both eyes), microphthalmia (abnormally small eye globe size) and many other eye malformations.
  • Color blindness. Genetically-based alteration associated to the X chromosome that affects the ability to properly perceive some colors due to a lack or malfunction of one of the retinal cone cells, responsible to differentiate between green, red, and blue colors.
  • Corneal dystrophies, a group of diseases that cause the loss of corneal transparency. The cornea is also a natural lens that should keep its transparency to facilitate vision.
  • Optic atrophy and hereditary optic neuropathies. The atrophy of the optic nerve causes a progressive vision loss due to damages in the optic nerve, and may have a hereditary cause. Another similar disease is Leber Hereditary Optic Neuropathy (LHON), in which mitochondrial inheritance plays an essential role.
  • Systemic diseases that affect vision Some systemic diseases with a hereditary basis, such as Graves disease (thyroid ophthalmopathy) and diabetes, may affect vision.

There are other highly prevalent diseases among general population, such as age-related macular degeneration and glaucoma, that are most likely to affect people having a direct kinship link with other affected people.

In addition, there are a large number of rare diseases (those affecting less than 1 in 2,000 people) that are genetic disorders that affect vision. While each of these diseases affects a small percentage of the general population, if we add them all up, we find that together they affect more than 300 million people worldwide.

Diagnosis of eye diseases with genetic factors

The genetic diagnosis of these diseases is not easy. On the one hand, 500 genes that can cause vision problems have been described. On the other hand, each one of these genes may present different variations (mutations). Moreover, like previously mentioned, most of the cases are caused by the interaction of several factors, both genetic and from the environment.

Thus, the finding of a mutation in one of these genes alone is often not enough to unequivocally confirm that the patient suffers from a certain disease, but it is just one more piece (that is, a key piece) of the puzzle that we must assemble to elucidate the alteration that the patient suffers from. Genetic testing is usually indicated once the clinical picture has been correctly studied.

Some people also want genetic counseling because they are considering having biological offspring, and these tests can help to analyze probabilities of inheritance.

For this reason, ophthalmologic examinations are especially recommended if there is a family history of diseases that may be hereditary and affect vision. These patients should undergo a complete ophthalmologic examination to rule out their presence or, if necessary, to apply early treatment.

Treatments and prognosis of eye diseases with genetic factors

Although diagnosis can be a great challenge for ophthalmology professionals, once there is confirmation that the patient has a certain genetic alteration in their DNA, they can be advised about changes in their diet or habits that can influence the probability of a certain disease manifesting or not, or modify the prognosis.

Many of these diseases currently have no proven cure. However, a lot of medical research is being conducted worldwide on these diseases and their treatments. There is currently a single approved gene therapy for retinal dystrophy associated with mutation in the ERP65 gene, but numerous clinical trials at different stages are currently being conducted for other genetic mutations responsible for inherited retinal disease.

Knowing the genetic basis of diseases that affect vision allows us to better understand the basis of the diseases, how to support retinal function in the best possible way and to objectively evaluate the possibilities of treatment with various therapies, such as gene therapies, which are beginning to become an emerging reality.

New Ocular Genetics Unit at ICR

At ICR we are also actively participating in clinical trials and different lines of investigation on eye diseases with genetic factors. Bearing that in mind, we have developed an ocular genetics unit from which, besides carrying out research, we assist patients with this kind of pathology in order to properly examine their case and monitor their evolution. Our goal is to provide a better prognosis for them and for future generations.

Like in the other departments at ICR, we take incorporate those scientifically proven innovations that could benefit the patients suffering from eye diseases with genetic factors. The medical team of the Ocular Genetics Unit will assess and inform each patient about their options.

Medical content revised by - Last revision 03/09/2024

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