What are the other Names for this Condition? (Also known as/Synonyms)

• CHED (Congenital Hereditary Endothelial Dystrophy)

What is Congenital Hereditary Endothelial Dystrophy? (Definition/Background Information)

• Congenital Hereditary Endothelial Dystrophy (CHED) is a rare genetic condition involving the cornea of both eyes. In this condition, the cornea is cloudy and shows fluid buildup, resulting in vision impairment from infancy
• Congenital Hereditary Endothelial Dystrophy forms part of a group of disorders named anterior segment developmental anomalies (ASDA). ASDA refers to a group of developmental disorders that involve the anterior segment region of the eye. These disorders are also termed anterior segment dysgenesis (ASD). The anterior segment anatomical region includes the cornea, lens, iris, and aqueous humor that nourishes the eye
• Congenital Hereditary Endothelial Dystrophy is a lifelong condition, and management often involves monitoring visual function, addressing complications such as glaucoma if present, and considering surgical interventions when necessary
• In severe cases where vision is significantly compromised, corneal transplantation may be considered as a treatment option. However, the success of transplantation can be influenced by factors such as the age of the individual and the presence of additional ocular abnormalities

Who gets Congenital Hereditary Endothelial Dystrophy? (Age and Sex Distribution)

• Congenital Hereditary Endothelial Dystrophy (CHED) is a rare condition that is grouped under congenital corneal opacities, which have an incidence of about 6 cases per 100,000 population
• CHED is a congenital disorder, and the presentation of symptoms may occur following the birth of the child (during early infancy)
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected. A very high frequency of the condition is noted among some countries of the Middle East (such as Saudi Arabia) and South Asia (such as India and Pakistan)

What are the Risk Factors for Congenital Hereditary Endothelial Dystrophy? (Predisposing Factors)

• A positive family history is a significant risk factor since Congenital Hereditary Endothelial Dystrophy is typically inherited
• Children born to consanguineous partners or spouses are at an even higher risk
• The condition is known to be associated with Harboyan syndrome (also known as corneal dystrophy-perceptive deafness)

It is important to note that having a risk factor does not mean one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Congenital Hereditary Endothelial Dystrophy? (Etiology)

Congenital Hereditary Endothelial Dystrophy (CHED) is a rare genetic eye disorder that affects the cornea, specifically the corneal endothelium. The corneal endothelium is a thin layer of cells on the inner surface of the cornea responsible for maintaining the cornea's clarity by regulating fluid balance.

• Mutations in the SLC4A11 gene (on chromosome 20p13) have been associated with CHED
• CHED forms part of a group of conditions known as anterior segment developmental anomalies. The condition typically develops due to a lack or abnormal development of the endothelial cells, resulting in endothelial dystrophy

In individuals with anterior segment developmental anomalies (ASDA), frequent disruptions in the aqueous humor production and drainage pathways result in complications, such as increased intraocular pressure, which results in glaucoma.

What are the Signs and Symptoms of Congenital Hereditary Endothelial Dystrophy?

The signs and symptoms of Congenital Hereditary Endothelial Dystrophy may vary from child to child and may be mild or severe. These include:

• Corneal edema (fluid buildup)
• Bilateral corneal opacity (cloudiness); the cornea may appear milky
• Light sensitivity
• Increased tearing
• Uncontrolled eye movement or nystagmus
• Both eyes are typically affected

How is Congenital Hereditary Endothelial Dystrophy Diagnosed?

The following observations and tests may help diagnose Congenital Hereditary Endothelial Dystrophy:

• Physical examination and medical history evaluation
• Assessment of signs and symptoms
• General eye exam
• Fundoscopic (ophthalmoscopic) examination by an eye specialist who examines the back part of the eye (or the fundus)
• Visual acuity test using a unique and standardized test chart (Snellen chart)
• Slit-lamp examination
• Gonioscopy, a painless eye exam using special devices
• Visual evoked potential (VEP) test
• Prenatal tests and newborn screening

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Congenital Hereditary Endothelial Dystrophy?

The complications of Congenital Hereditary Endothelial Dystrophy may include:

• Emotional stress for the parents and caregivers
• Increased intraocular pressure leading to glaucoma (causing optic nerve damage and vision loss)
• Development of amblyopia (lazy eye)
• Individuals with Harboyan syndrome may present hearing loss
• Decreased quality of life
• Post-treatment complications

How is Congenital Hereditary Endothelial Dystrophy Treated?

The treatment measures for Congenital Hereditary Endothelial Dystrophy may include:

• Symptomatic management
• Decrease intraocular pressure through eye drops and medications
• Surgical intervention may be necessary, including corneal transplant (keratoplasty) and Descemet's stripping endothelial keratoplasty (DSEK)
• Correction of refractive errors, if any, including the use of eyeglasses or contact lenses
• Close follow-up and periodic visits to the healthcare provider is important

The treatment measures include treating the symptoms and managing any associated condition/disorder.

How can Congenital Hereditary Endothelial Dystrophy be Prevented?

There are no specific methods or guidelines to prevent Congenital Hereditary Endothelial Dystrophy since it is a genetic condition.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as anterior segment developmental anomalies

What is the Prognosis of Congenital Hereditary Endothelial Dystrophy? (Outcomes/Resolutions)

• The prognosis of Congenital Hereditary Endothelial Dystrophy depends on the severity of the condition and one’s response to treatment. An early diagnosis and prompt medical intervention can help improve the outcomes
• Individuals with mild conditions have a better prognosis than those with severe symptoms and complications. Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Congenital Hereditary Endothelial Dystrophy:

The following DoveMed website link is a helpful resource for additional information:

https://www.dovemed.com/diseases-conditions/glaucoma