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

• Microcornea-Cataract Syndrome

What is Cataract Microcornea Syndrome? (Definition/Background Information)

• Cataract-Microcornea Syndrome is characterized by the association of congenital cataract and microcornea without any other systemic anomaly or dysmorphism
• Clinical findings include a corneal diameter inferior to 10 mm in both meridians in an otherwise normal eye, and an inherited cataract, which is most often bilateral posterior polar with opacification in the lens periphery
• The cataract progresses to form a total cataract after visual maturity has been achieved, requiring cataract extraction in the first to third decade of life
• Microcornea-Cataract Syndrome can be associated with other rare ocular manifestations, including myopia, iris coloboma, sclerocornea and Peters anomaly
• Ophthalmologic and general examination allows other syndromes to be excluded
• Transmission is in most cases autosomal dominant, but cases of autosomal recessive transmission have recently been described
• To date, more than 15 families showing Microcornea-Cataract Syndrome have been described

(Source: Cataract Microcornea Syndrome; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

Who gets Cataract Microcornea Syndrome? (Age and Sex Distribution)

• Cataract Microcornea Syndrome is an extremely rare congenital disorder. The presentation of symptoms may occur after the birth of the child
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Cataract Microcornea Syndrome? (Predisposing Factors)

• A positive family history may be an important risk factor, since Cataract Microcornea Syndrome can be inherited
• It may be also associated in some cases, with other eye-related disorders including:
  • Peters anomaly
  • Shortsightedness
  • Iris coloboma
  • Sclerocornea

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 Cataract Microcornea Syndrome? (Etiology)

• There is marked genetic heterogeneity. Mutations have been described in several crystallin genes (CRYAA, CRYBB1, CRYGD), and in the gap junction protein alpha 8 gene (GJA8)
• Transmission is in most cases autosomal dominant, but cases of autosomal recessive transmission have recently been described

(Source: Cataract Microcornea Syndrome; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly function gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Cataract Microcornea Syndrome?

The signs and symptoms of Cataract Microcornea Syndrome may include:

Very frequently present symptoms in 80-99% of the cases:

• Cataract
• Microcornea

Frequently present symptoms in 30-79% of the cases: Myopia

Occasionally present symptoms in 5-29% of the cases:

• Corneal dystrophy
• Corneal opacity
• Iris coloboma
• Nystagmus

(Source: Cataract Microcornea Syndrome; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Cataract Microcornea Syndrome Diagnosed?

Cataract Microcornea Syndrome is diagnosed on the basis of the following information:

• Complete physical examination and eye examinations
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests
• Imaging studies
• Biopsy studies, if necessary

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 Cataract Microcornea Syndrome?

The complications of Cataract Microcornea Syndrome may include:

• Loss of vision
• Reduced quality of life

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Cataract Microcornea Syndrome Treated?

• Cataract surgery has to be performed in order to restore visual acuity and avoid amblyopia in individuals with Cataract Microcornea Syndrome

(Source: Cataract Microcornea Syndrome; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

How can Cataract Microcornea Syndrome be Prevented?

Currently, Cataract Microcornea Syndrome may not be preventable, since it is a genetic disorder.

• 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

Regular medical screening at periodic intervals with tests and physical examinations are recommended.

What is the Prognosis of Cataract Microcornea Syndrome? (Outcomes/Resolutions)

• Visual acuity after uncomplicated cataract extraction is relatively good

(Source: Cataract Microcornea Syndrome; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

Additional and Relevant Useful Information for Cataract Microcornea Syndrome:

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

http://www.dovemed.com/diseases-conditions/rare-disorders/