Did you know that cataracts are the leading cause of blindness worldwide? This common aging-related condition affects more than half of all Americans 80 years and older. While no clear causative factor has been identified, studies have reported over 100 genes that can increase the risk of cataracts. Mutations in these genes can be passed down in the family, suggesting that some cases of cataracts may be hereditary. The article discusses the genetic landscape of cataracts and outlines some possible preventative measures.
Cataracts: An Overview
In a normal, healthy eye, the lens is clear.
In cataracts, the lens gets clouded due to an eye protein that breaks down and clumps together as a part of the aging process.
As a result, the light rays cannot pass through the lens and focus on the retina (the tissue that acts as the screen for images in the eye).
In the initial stages, cataracts do not cause any issues.
However, as they grow over time, it affects more of the lens, making it difficult for you to see.
While cataracts do not spread from one eye to the other, some people may develop cataracts in both eyes.
Types Of Cataracts
There are four types of cataracts:
- Age-related: The majority of cataracts develop due to aging.
- Congenital: Some children are born with cataracts, while a few may develop the condition in childhood.
While some congenital cataracts do not affect eyesight, the ones that do may need removal to improve vision. - Secondary: These cataracts develop due to other health conditions, like diabetes. Some secondary cataracts also occur due to steroid use.
- Traumatic: An injury to one or both eyes may result in the development of a cataract. This may happen right after an accident or a few years later.
Symptoms
The following symptoms are commonly noted in the case of cataracts.
If you experience two or more of these symptoms, it is recommended to get them checked by an ophthalmologist:
- Blurry vision
- Seeing a double or a ghosted image from the affected eye
- Extra sensitivity to light (for example, with oncoming headlights at night)
- Difficulty in seeing at night
- Needing more light when reading
- Seeing bright colors as faded ones
Causes And Risk Factors
Though the exact cause of cataracts is unknown, a few potential reasons why they occur include:
- Diabetes
- Smoking
- Excessive time in the sun
- Use of steroids
- Diuretics
- A few types of tranquilizers
More research is required to understand the causes of cataracts.
Congenital vs. Age-related Cataracts
Aging is the most common cause of cataracts.
This condition is due to cumulative changes that occur in the eyes after 40 years of age.
Congenital cataract, on the other hand, is present at birth.
This type of cataract is rare and may be present as part of birth defects in Down Syndrome, Trisomy 13, Pierre-Robin Syndrome, Chondrodysplasia syndrome, and others.
Are Cataracts Hereditary?
Yes, cataracts can be hereditary.
Congenital cataracts, which occur at birth, are often caused by genetic mutations and can run in families.
Additionally, age-related cataracts may also have a hereditary component, as genetic factors can influence the shape and integrity of the lens, making it more susceptible to clouding.
Research has identified over 115 genes and 38 disease-causing genes associated with cataract formation. A twin eye study demonstrated that heritability accounts for 53% to 58% of the cortical cataracts risk and 48% of nuclear cataracts risk.
Do Cataracts Run In Families?
Yes, cataracts can run in families.
- Congenital cataracts: Over 50% of cases of congenital cataracts are considered to have a genetic cause that can be inherited.
- Age-related cataracts: The risk of having cataracts increases when you have biological parents, brothers, sisters, or other family members who have them.
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Genetics Mechanisms In Cataracts
Abnormal changes (mutations) in crystallins (a type of eye lens protein) or other lens proteins may lead to protein aggregation.
This results in congenital cataracts.
When these genetic mutations increase the susceptibility of the eye to environmental insults like light, oxidative or hyperglycemic damage, they may result in age-related cataracts.
Hereditary congenital cataracts are inherited in Mendelian fashion, while age-related cataracts are influenced by multiple genes and environmental factors.
Specific Genes Implicated In Inherited Cataracts
Several genes have been identified to cause congenital cataracts:
- PANK4
- EPHA2
- FOXE3
- GJA8
- IARS2
- CTRCT29
- CRYGA
- CRYGB
- CRYGC
- CRYGD
- WFS1
- GCNT2
- AGK
- EYA1
- CTPL1
- TRPM3
Are There Any Ways To Prevent Hereditary Cataracts?
Unfortunately, there is no way to prevent hereditary cataracts.
However, timely detection and treatment of hereditary cataracts may help restore clear vision.
Other Risk Factors For Cataracts
Besides genetics, several other factors may increase your risk of developing cataracts.
Who Is At The Most Risk Of Getting Cataracts?
Your risk of cataracts increases with age.
Other risk factors for cataracts include:
- Having health conditions like diabetes
- Smoking (even second-hand smoke)
- Excessive alcohol consumption
- Having an eye injury, surgery to the eye or radiation treatment to the upper part of the body
- Spending a lot of time in the sun
- Taking steroids for other medical conditions
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Tips To Lower Your Risk For Cataracts
While you cannot prevent cataracts from occurring, you can reduce your risk for the same.
Here are some ways to do so:
- Protect your eyes from the sun: Wearing sunglasses and a cap or hat that blocks sunlight from reaching your eyes may help lower your risk of cataracts.
- Protect your eyes from injury: Prevent accidental injuries to your eyes. Wear protective eyewear whenever possible.
- Quit smoking: Since smoking is a risk factor for cataracts, quitting the habit may help lower your risk.
- Eat a healthy diet: Eating healthy foods rich in nutrients like vitamin A may help lower your risk for cataracts.
Summary: Are Cataracts Hereditary?
- Cataracts happen when eye proteins break down and clump together, clouding the lens of the eye and causing vision problems.
- Common symptoms include blurry vision, double vision, light sensitivity, difficulty seeing at night, needing more light for reading, and seeing faded colors.
- Genetic factors play a significant role in the development of cataracts, with over 100 genes linked to an increased risk.
- Mutations in these genes account for up to 50% of congenital cataracts and 48-58% of risk of age-related cataracts.
- Besides genetics, factors like diabetes, smoking, excessive sun exposure, steroid use, and certain medications contribute to cataract development.
- Practical ways to lower the risk of cataracts include protecting the eyes from injuries and sun exposure, quitting smoking, and eating a diet rich in nutrients.
