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

• BCD (Bietti Crystalline Dystrophy)
• Bietti Crystalline Corneoretinal Dystrophy
• Bietti Tapetoretinal Degeneration with Marginal Corneal Dystrophy

What is Bietti Crystalline Dystrophy? (Definition/Background Information)

• Bietti Crystalline Dystrophy (BCD) is a rare inherited eye disorder wherein yellow white crystalline lipid deposits are observed in the retina, and occasionally, in the cornea
• It causes a gradual decrease in one’s visual acuity, causing along-with it, night blindness and impaired color vision. Both eyes are typically affected
• Bietti Crystalline Dystrophy has no effective treatment and usually leads to complete vision loss in many individuals

Who gets Bietti Crystalline Dystrophy? (Age and Sex Distribution)

• Bietti Crystalline Dystrophy is an uncommon disorder; the prevalence of the condition is around 1 in 67,000
• It is usually detected during early teenage and young adulthood (in up to the third decade). Rarely, it can be (first) diagnosed in older adults
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected. However, a greater number of cases are noted in Asians, especially in individuals of Chinese and Japanese ethnicity (East Asian descent)

What are the Risk Factors for Bietti Crystalline Dystrophy? (Predisposing Factors)

• A positive family history is an important risk factor, since Bietti Crystalline Dystrophy is typically inherited
• Children born to consanguineous partners or spouses may have a higher risk for this condition

It is important to note that having a risk factor does not mean that 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 that 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 Bietti Crystalline Dystrophy? (Etiology)

Bietti Crystalline Dystrophy (BCD) is a genetic disorder that is inherited in an autosomal recessive manner.

• BCD is caused by an abnormal variant of the CYP4V2 gene, which is transmitted in autosomal recessive manner. The dysfunctional gene results in complex lipid deposition in crystalline form in the retina and/or cornea
• Such abnormal lipid deposits can be detected in various organs in the body suggesting a systemic disorder rather than one that is just confined to the eye

What are the Signs and Symptoms of Bietti Crystalline Dystrophy?

The signs and symptoms of Bietti Crystalline Dystrophy may vary from one individual to another. These signs and symptoms include:

• Progressive worsening visual acuity: the rate of progression may vary widely between the affected individuals
• Night blindness
• Visual field loss
• Impaired color vision
• Both eyes are typically involved (bilateral condition)

How is Bietti Crystalline Dystrophy Diagnosed?

Bietti Crystalline Dystrophy (BCD) may be diagnosed by the following observations and tests:

• 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). The ophthalmoscopic exam may show yellow-white retinal crystalline deposits. BCD is a progressive condition that is associated with the presence of retinal pigment epithelium (RPE) degeneration and sclerosis of the blood vessels of the choroid
• Visual acuity test using a special and standardized test chart (Snellen chart)
• Slit-lamp examination
• Humphrey visual field test
• Visual evoked potential (VEP) test
• Electroretinography
• In vivo confocal and specular microscopy
• Spectral domain optical coherence tomography (OCT) of eye
• Molecular genetic testing, if necessary

The diagnosis is a combination of clinical findings and imaging studies; a confirmation is done through molecular testing for the involved genes.

A differential diagnosis to eliminate other conditions may be considered, before arriving at a definitive diagnosis. These may include:

• Cystinosis
• Drug toxicity from various agents
• Infectious crystalline keratopathy
• Primary hyperoxaluria type 1 and 2
• Retinitis pigmentosa
• Sjogren-Larsson syndrome

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 Bietti Crystalline Dystrophy?

The complications of Bietti Crystalline Dystrophy may include:

• Emotional stress
• Irreversible vision loss resulting in blindness
• Decreased quality of life

How is Bietti Crystalline Dystrophy Treated?

• Bietti Crystalline Dystrophy is a progressive disorder with no known surgical and medical treatments
• An early diagnosis can help individuals in receiving appropriate social and occupational accommodation
• Routine follow-up visits to the ophthalmologist is highly recommended

How can Bietti Crystalline Dystrophy be Prevented?

Currently, there are no specific methods or guidelines to prevent Bietti Crystalline 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

What is the Prognosis of Bietti Crystalline Dystrophy? (Outcomes/Resolutions)

Bietti Crystalline Dystrophy is a progressive disorder with no cure. It leads to legal blindness in a majority of affected individuals.

Additional and Relevant Useful Information for Bietti Crystalline Dystrophy:

Please visit our Eye & Vision Health Center for more physician-approved health information:

https://www.dovemed.com/health-topics/vision-center/