Leber congenital amaurosis

 

Leber congenital amaurosis

Definition

This is a rare kind of blindness or severely impaired vision caused by a defect transmitted as an autosomal recessive trait and occurring at birth or shortly thereafter.

This also is called amaurosis congenital of Leber's, congenital retinal blindness, hereditary epithelial aplasia, and retinal aplasia.

Source : Health Central 

 

Organ

This disease affects the retina, which gradually deteriorates.

 

Symptoms

There are many different types of LCA, and the disease can present differently in different children. However, there are some basic symptoms that are often associated with LCA. These include nystagmus (involuntary jerky rhythmic eye movement), photophobia (sensitivity to light) and slow pupillary response to light. Eye-pressing and rubbing the eyes with a knuckle or finger can be common with babies and children who have very little vision. This can cause damage to the cornea (keratoconus) and lens and may result in a loss of fatty tissue around the eyes causing the eyes to look deep-set. 

Source : Retina International

 

Frequency

The prevalence of LCA is 1/50,000 - 1/33,000 live births and accounts for 5% of all retinal dystrophies and 20% of blindness in school age children.

Source : Orphanet 

Causes

LCA is a very rare condition which is estimated to affect around 1 in 80,000 in the population. Forms of LCA are caused by a mutation in one of a number of genes that are important for retinal function and it is usually inherited in an autosomal recessive manner. However, there are rare incidences where the inheritance pattern may be autosomal dominant.

Source : Retina International

 

Evolution

The extent of degeneration depends on the type of LCA the child has and for some types of LCA the vision (or lack of vision) remains stable.

Source : Retina International

 

Diagnosis

LCA is usually diagnosed by an ophthalmologist based on history and the physical findings on exam. An electroretinogram (ERG) is often utilized to test the function of the rods and cones of the retina and is performed with special equipment. Other modalities that have been explored and assist with evaluation include optical coherence tomography (OCT) and autofluorescence imaging of the retina. If LCA is suspected clinically, genetic testing should be performed. Almost 80% of patients will have a diagnostic genetic test which can aid in prognosis, family planning, and determining treatment options. Specific genetic subtypes of LCA predispose patients to nephronophthisis and kidney failure; patients with these genetic subtypes should be referred to a nephrologist. Genetic testing can identify carriers of the condition among other family members. Genetic counseling is recommended for affected families.

Source : AAPOS

 

Treatment

Currently LCA is an incurable disease. Treatment is mainly supportive and includes correction of refractive error and use of low-vision aids. Repeated poking and pressing on the eyes should be discouraged. Periodic ophthalmic evaluation and assessment of the presence of amblyopia, glaucoma, or cataract should be achieved. Therapies are presently being investigated, including gene therapy (particularly for RPGRIP and CEP290) and optogenetics (genetic targeting of light-sensing molecules to residual cells in a degenerate retina).

Source : Orphanet 

 

 

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