How Does Genetics Elevate the Potential Risk of Glaucoma?

Latest Posts

Table of Contents

How Does Genetics Elevate the Risk of Glaucoma?

Date of Content: June 17, 2024
Written by: Catherine Alcalde
Reviewed by: Maarit Tiirikainen, PhD

Facebook
Twitter
LinkedIn

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

What Is Glaucoma?

Glaucoma is known to be one of the primary causes of permanent blindness in the world. It’s defined as a serious eye condition where damage to the optic nerve can result in peripheral vision loss to complete permanent blindness if not diagnosed and treated early.

Genetics plays a big part in how likely someone is to get glaucoma. Therefore, gaining insight into the various types of glaucoma, the factors that increase the likelihood of developing it, and the treatment options available is important for effectively managing this condition.

Types of Glaucoma

Primary Open-Angle Glaucoma (POAG): This is the most common type of glaucoma that progresses slowly, typically without any noticeable symptoms in the early stages. POAG is usually painless and does not cause immediate vision loss. However, as it progresses gradually, it often remains undetected until considerable damage to the optic nerve has occurred.

Primary Angle-Closure Glaucoma (PACG): Also known as closed-angle or narrow-angle glaucoma. This occurs when your iris, the colored part of your eye, gets too big and blocks the fluid from draining properly. This leads to an increase in pressure inside your eye. When it suddenly happens, it’s called acute angle-closure glaucoma, and it causes eye pain, a red eye, and nausea. It’s crucial to seek urgent medical attention for this condition.

Normal-Tension Glaucoma: The condition may arise from an optic nerve overly sensitive to pressure changes or compromised blood supply due to factors such as atherosclerosis, or the thickening of the arteries. This highlights the complexity of the diagnostics of glaucoma, where factors beyond intraocular pressure (IOP) play critical roles in disease progression. This aspect complicates diagnosis, as symptoms such as visual changes and eye discomfort can manifest even with seemingly normal pressure levels.

Secondary Glaucoma: Secondary glaucoma arises when elevated pressure within the eye is triggered by an underlying condition, such as eye trauma, severe inflammation (uveitis), or certain medical conditions (e.g. systemic hypotension, diabetes mellitus) and medications (e.g. steroids and some types of antidepressants and antihypertensives). Symptoms may vary depending on the underlying cause but commonly include visual disturbances, eye discomfort, and redness.

What Causes Glaucoma?

Glaucoma’s primary cause is increased fluid pressure within the eye, which can harm the optic nerve. However, there are additional factors to consider:

Impaired Drainage Pathways:  As we age, the eye’s drainage system can become less effective over time, making it harder for fluid called aqueous humor to flow out properly. This inefficiency can result in fluid buildup within the eye, leading to increased intraocular pressure.

Genetic Factors: Family history is a crucial factor in assessing an individual’s risk of glaucoma. Genetic predispositions can significantly increase the chances of developing this condition, emphasizing the need to understand one’s familial medical background to comprehend potential risks.

Increased Intraocular Pressure (IOP): This refers to elevated pressure within the eye that causes stress on the optic nerve which could lead to vision impairment. 

Eye Injuries and Severe Inflammation: These conditions can significantly increase the risk of developing glaucoma. Physical trauma to the eye or too much inflammation affecting ocular tissues can disrupt normal eye function. This disruption can lead to increased intraocular pressure, contributing to the development and progression of glaucoma.

What Are the Symptoms of Glaucoma?

Glaucoma’s symptoms can vary depending on the specific type of the condition. Open-angle glaucoma often goes unnoticed in its initial stages, without any symptoms showing but gradually results in peripheral vision impairment characterized by patchy blind spots. As the condition progresses, central vision may also be affected. 

Acute angle-closure glaucoma, on the other hand, presents with severe symptoms including headache, intense eye pain, nausea, blurred vision, halos around lights, eye redness, and sometimes vomiting. Normal-tension glaucoma, despite lacking early symptoms, may eventually lead to blurred vision followed by the loss of peripheral vision in advanced stages. 

Glaucoma in children is marked by subtler signs such as a dull or cloudy eye, increased blinking, tears without crying, blurred vision, worsening nearsightedness, and headaches. 

How Is Glaucoma Diagnosed?

The diagnosis of glaucoma requires a comprehensive eye examination. This procedure encompasses various steps, including measuring intraocular pressure, examining the drainage angle, evaluating the optic nerve for indications of damage, conducting visual field tests, and assessing corneal thickness. Consistent eye check-ups play a critical role in the early detection of glaucoma and the preservation of visual acuity.

Genetics Predisposition of Glaucoma

Genome-wide Association Studies (GWAS) have provided valuable genetic information about glaucoma, helping us to understand the complex mechanisms behind optic nerve damage that could lead to vision loss. By examining the genetics behind glaucoma, we can understand the roles of certain genes in how they increase the disease’s developing risks and progression. These research findings aim to offer supportive insights into how genetic factors influence glaucoma that may be applied in developing personalized treatment strategies based on individual genetic profiles.

Most current studies have supported potential therapeutic targets for some patients with early-onset glaucoma by examining the molecular and cellular events caused by identified MYOC, OPTN, and TBK1 mutations. Genes that are associated with the complex inheritance of common adult-onset glaucoma are also identified. 

Primary open-angle glaucoma:

ABCA1

ATP binding cassette subfamily A member 1 (ABCA1) is a protein that has an important role in maintaining cellular integrity within the eye, particularly through its facilitation of cholesterol and phospholipid transport. Research highlights ABC1’s importance in regulating intraocular pressure and supporting optic nerve function, both crucial aspects of eye health. However, variants in the ABCA1 gene may influence the development of primary open-angle glaucoma (POAG by impacting these functions).

AFAP1

The Actin Filament Associated Protein 1 (AFAP1) gene is involved in organizing the actin cytoskeleton and facilitating cellular signaling processes. 

The study has identified that AFAP1 plays a critical role in maintaining the structural integrity of trabecular meshwork cells and optic nerve head astrocytes. These cells are essential for regulating the outflow of aqueous humor and preserving optic nerve health. Disruptions in AFAP1-mediated processes may lead to abnormalities in cytoskeletal organization, potentially influencing increased intraocular pressure and optic nerve damage, characteristic of glaucoma.

Primary angle-closure glaucoma:

ABCC5

ABCC5 is also known as multidrug resistance-associated protein 5 (MRP5). It is a protein involved in moving various substances across cell membranes. While the ABCC5 is primarily studied in the context of drug resistance, recent genetic studies have associated it with glaucoma.

A 2014 study has identified ABCC5 gene association with primary angle-closure glaucoma (PACG). A  particular rs1401999 SNP  in the ABCC5 is being linked to influence susceptibility risk to PACG. This SNP is associated with altered expression of ABCC5,  which may affect the regulation of intraocular pressure and contribute to the development of PACG.

Exfoliation syndrome (XFS) and glaucoma

LOXL1

The Lysyl oxidase-like 1 (LOXL1) gene produces a protein involved in elastogenesis (the formation of elastic fibers) and collagen cross-linking (strengthening collagen fibers within the extracellular matrix). The presence of SNPs rs1048661, rs2165241, and rs3825942 have been strongly associated with exfoliation syndrome (XFS), a condition characterized by abnormal deposits in various tissues, including the eye’s lens capsule, which can lead to secondary open-angle glaucoma. 

LOXL1’s role in maintaining extracellular matrix stability suggests a potential connection to structural changes in the eye’s anterior segment, influencing the development of primary angle closure glaucoma  (PACG). 

Non-Genetic Risk Factors for Glaucoma

Several factors contribute to the development of glaucoma, a condition characterized by optic nerve damage and vision loss. Age is a significant risk factor, particularly beyond 40 years old, indicating an increased vulnerability with the advancing age. Eye Injuries, particularly those causing trauma and severe inflammation, refractive errors like farsightedness or nearsightedness, and systemic health conditions and medications are other known contributing factors that could further increase the risk of developing glaucoma.

 

Can Glaucoma Be Treated?

Although damage caused by glaucoma is irreversible, treatment can effectively stop further damage. Various treatment options are available, including:

Medication: Eye drops are a common treatment method for reducing eye pressure in glaucoma. They work by decreasing the aqueous humor production or enhancing its outflow from the eye. This simple and effective approach helps manage the condition by targeting the underlying cause of elevated eye pressure, thus preserving vision and preventing further damage to the optic nerve.

Laser Surgery: These are minimally invasive surgical techniques like Laser trabeculoplasty and Iridotomy where procedures are utilized to enhance the drainage of fluid from the eye, reducing intraocular pressure, a primary factor in glaucoma progression. Laser trabeculoplasty targets the trabecular meshwork, enhancing its drainage capacity, while iridotomy creates a small opening in the iris, enabling fluid outflow. 

Trabeculectomy: This common glaucoma surgery involves making a small flap in the white part of the eye called the sclera and forming a reservoir or filtering bleb under the transparent covering of the eye called the conjunctiva. This setup enables the aqueous humor to drain from the eye, reducing intraocular pressure and minimizing the risk of optic nerve damage,  helping to preserve vision.

Minimally Invasive Glaucoma Surgery (MIGS): This treatment involves several less invasive techniques designed to improve fluid drainage, reduce complications, and shorten recovery times. It creates new drainage pathways in the eye, effectively lowering intraocular pressure with fewer risks compared to traditional surgeries

References

  1. https://www.aao.org/eye-health/diseases/what-is-glaucoma
  2. https://glaucoma.org/articles/the-genetics-of-glaucoma
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6074793/
  4. https://www.brightfocus.org/glaucoma/article/glaucoma-what-your-genetic-risk
  5. https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/glaucoma?sso=y
  6. https://www.hopkinsmedicine.org/health/conditions-and-diseases/glaucoma
  7. https://glaucoma.org/articles/the-genetics-of-glaucoma
  8. https://www.aao.org/eye-health/diseases/what-is-cataract-surgery
  9. https://www.aao.org/eye-health/diseases/glaucoma-drainage-implants
  10. https://www.ncbi.nlm.nih.gov/books/NBK532237/#:~:text=
  11. https://www.google.com/search?q=atherosclerosis+meaning&oq=atherosclerosis
  12. https://medlineplus.gov/genetics/gene/abca1/
  13. https://www.genecards.org/cgi-bin/carddisp.pl?gene=AFAP1
  14. https://www.ncbi.nlm.nih.gov/gene/2762
  15. https://medlineplus.gov/genetics/gene/pmm2/
  16. https://www.genecards.org/cgi-bin/carddisp.pl?gene=TGFBR3
  17. https://www.mayoclinic.org/diseases-conditions/glaucoma/diagnosis-treatment/drc-20372846
  18. https://glaucoma.org/types/secondary-glaucoma
  19. https://www.aao.org/eye-health/anatomy/aqueous-humor
  20. https://www.mayoclinic.org/diseases-conditions/glaucoma/symptoms-causes/syc-20372839
  21. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945113/
  22. https://www.genecards.org/cgi-bin/carddisp.pl?gene=LOXL1
  23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945113/

Customer Reviews

Christopher Devlin
Christopher Devlin
LifeDNA Customer
Read More
I am so impressed with this service. I have even discussed these recommendations with my health care providers and they are all impressed too! I can’t compare it with other services as I have only tried this but I recommend. Also I think I pulled my genetics in from ancestry too which was super convenient.
Lei'a
Lei'a
LifeDNA Customer
Read More
Great source of information I was looking for a platform to make use of my existing raw data from Ancestry. I’m glad I found LifeDNA. I originally took a DNA test to learn about my roots and it’s great to know that my DNA could also play a big role in my health, diet, and even my skin. Overall, all the reports are incredible.
Shiraz Dole
Shiraz Dole
LifeDNA Customer
Read More
It is crazy how I felt that I had a strong understanding of my bodies needs, but after having my DNA analyzed by the LifeDNA team, I realized that there was so much I still did not know.
Doc Sheila Lim
Doc Sheila Lim
LifeDNA Customer
Read More
I got some pretty useful insight that helped me with my diet.
Previous
Next

*Understanding your genetics can offer valuable insights into your well-being, but it is not deterministic. Your traits can be influenced by the complex interplay involving nature, lifestyle, family history, and others.

Our reports and suggestions do not diagnose or treat any health conditions or provide any medical advice. Consult with a healthcare professional before making any major lifestyle changes or if you have any other concerns about your results.