Do Cataracts Run in Your Family?

Yes, you can inherit cataracts from your parents.

A cataract is an eye condition marked by a cloudy formation inside the eye lens. It can be passed down through genetic mutations.

These mutations affect different components in the eye, making it harder for the lens to stay clear. Severe mutations can lead to cataracts from birth, while milder ones increase the risk of developing cataracts as you age.

Cataracts can range from translucent to opaque, depending on its severity.

People often associate cataracts with old age. While the condition is often age-related, it can affect anyone.

Geneticists have identified genes linked to inherited cataracts and genetic factors of age-related cataracts.¹

The list of genes associated with cataracts is far from complete. However, current research explains the link between genetic heterogeneity and cataracts.

Genetic heterogeneity refers to different genetic defects that cause the same disorder. It usually occurs when the mutation happens at different points on the same gene.

How Cataracts Form in the Eye

Your eye’s lens is normally clear. It allows the light to come through and helps focus it as it enters the eye. 

The lens is made up of water and proteins. The protein arrangement doesn’t affect the transparency of the lens and permits the light to pass through with ease.² 

Cataracts form when these proteins lump, resulting in a cloudy appearance.²

The cloud formation becomes denser as the cataract progresses. It disperses and blocks the light coming into your lens, which makes everything unclear and blurry through your retina.

When the center of the lens of the eye becomes cloudy, causing blurred vision, it is called nuclear cataract.

The factors that can cause changes in the protein arrangement or density include:

• Aging
• Genetics
• Environmental factors

Symptoms of cataracts

When your cataract is still mild, you may not notice any symptoms. But as the condition worsens, you may experience changes, such as:

• Dim or blurred vision
• Visual impairment
• Seeing double in one eye
• Sensitivity to glare and bright light
• Difficulty seeing at night
• Seeing halos around lights
• Perceiving colors as faded or yellowish

Be sure to see your eye doctor as these signs may indicate other eye problems, too. 

Types of Cataracts

The classifications of cataracts based on the age of onset are congenital, pediatric, pre-senile, and age-related.

Congenital Cataracts

Other names: Infantile cataracts

Congenital cataracts are present at birth or in the first year of life. The American Academy of Ophthalmology cites that three to four per 10,000 live births yearly have infantile cataracts.³ 

It is the leading cause of five to 20% of childhood visual impairment and blindness.

Doctors recommend getting cataract surgery months after birth. At this time, the lens is still developing. Early cataract surgery and additional treatments prevents "lazy eye" and cataract blindness.

Congenital cataracts may be a symptom of metabolic disorders or genetic diseases.⁴ Lowe syndrome and type 2 neurofibromatosis are some illnesses that may cause congenital cataracts.⁵

Hereditary Congenital Cataract

Other names: Inherited congenital cataract

Inherited cataracts account for 8.3% to 25% of all congenital cataracts. About 70% of cases are isolated cataracts while 30% of inherited nuclear cataracts occur with other eye disorders or diseases.⁶

Eye lens mutations cause most cataracts that are present at birth. These mutations can cause inborn cataracts on both eyes (bilateral) or just on one eye (unilateral).

The two main types of inherited congenital cataracts are:

• Autosomal dominant congenital cataracts — These have an autosomal dominant pattern, meaning a single copy of a mutated gene is enough to cause cataracts.
• Autosomal recessive congenital cataracts — These have an autosomal recessive pattern, meaning two copies of a mutated gene are required to cause cataracts.

Hereditary congenital cataracts are inherited through non-sex chromosomes called autosomes. A child’s sex doesn’t affect their risk for an inherited cataract.

Isolated vs. Complex Congenital Cataracts

An isolated cataract occurs alone, and the genetic mutation affects only the eye lens. Complex congenital cataracts affect different parts of the eye structure. They are often accompanied by ocular defects, such as:

• Aniridia (an eye disorder where there is complete or partial absence of the iris)
• Microphthalmia (a birth defect where one or both eyes remain small because they failed to develop fully)
• Retinal degeneration
• Developmental anomalies of the eye

Pediatric Cataract

Other names: Childhood cataract, juvenile cataract

Pediatric cataract is one of the leading causes of visual impairment in older children. It’s responsible for five to 20% of pediatric blindness and visual impairment globally.⁷

It requires early treatment and long-term management. Otherwise, it can lead to lifelong blindness.

Known causes of pediatric cataracts include:

• External factors such as eye trauma
• Autosomal recessive inheritance — A way a genetic trait or condition is caused by gene mutations passed down from each parent
• Autosomal dominant inheritance — A way a genetic trait or condition is caused by gene mutations passed down from one parent

Hereditary Childhood Cataract

About half of childhood cataracts are hereditary. Mutations that disrupt the lens cell homeostasis cause hereditary juvenile cataracts.⁸ 

Unlike congenital cataracts, which appear at birth, they occur at a later age.

Most mutations occur as autosomal dominant cataracts, such as:

• Anterior polar cataract 1 and 2 — Both types feature small opacities on the anterior (nearer the front) eye lens.
• Posterior polar cataract 1 — A type of autosomal dominant cataract with opacities forming behind the lens.
• Posterior polar cataract 3 (also called a posterior subcapsular cataract.) — A type that causes a progressive disc-shaped cataract on the posterior subcapsular section. 

Below is an image of the cross-section of the eye lens

Acquired Childhood Cataract

Acquired cataracts form after exposure to external factors.

Eye trauma is the leading cause of childhood cataracts. In general, children are more prone to eye injuries because their motor skills aren't fully developed.

Metabolic and systemic disorders may also lead to the development of cataracts, such as:

• Myotonic dystrophy – A multi-system degeneration that affects the skeletal, smooth, and cardiac muscles
• Warburg micro syndrome — A rare genetic disorder marked by eye problems and issues with the development of the brain

Pre-Senile Cataract

Pre-senile cataracts occur between the ages of 18 to 45.

Genetics and external factors both play roles in their development. Posterior subcapsular cataract commonly affects this age group. It is a type of autosomal dominant cataract.

Other risk factors for pre-senile cataracts are:

• Smoking and tobacco consumption
• Alcohol intake
• High cholesterol diet
• Exposure to fuel and smoke

These external factors can also worsen pre-existing inherited cataracts and lead to vision loss.

Age-Related Cataract

Other names: senile cataract

Age-related cataracts appear after the age of 45. Its common cause is cumulative damage to lens proteins. Genetic mutations that interfere with lens cell balance may also cause age-related cataracts.

Structural proteins called crystallins make up the eye lens. There are two main kinds:⁹

• Alpha-crystallins help the lens tolerate age-related decline. They also prevent abnormal protein activities.
• Beta- and gamma-crystallins assist in lens development.

Aging causes beta-gamma-crystallins to lose their structure. Alpha-crystallins release distorted beta-gamma crystallins to the cytoplasm rather than rebuilding them. 

Distorted crystallins build up over time and form a complex. When they overcome the alpha-crystallins, they form into an insoluble protein, which is the cataract.

How To Know If You’re at Risk for Cataracts

Early diagnosis and treatment are vital in preventing the visual impairment and eye damage cataracts cause. Genetics is a major cause of cataracts across all age groups. 

DNA testing can check if you’re at risk for nuclear cataract formation. Studies show that advanced genetic testing can diagnose some rare diseases connected to childhood visual impairment and blindness.¹⁰