Amaurosis congenita of Leber, type 2

Amaurosis congenita of Leber, type 2
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Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Severe vision loss from birth
Complications	N/A
Onset	Congenital
Duration	Lifelong
Types	N/A
Causes	Genetic mutation in the RPE65 gene
Risks	N/A
Diagnosis	Genetic testing, electroretinography
Differential diagnosis	N/A
Prevention	N/A
Treatment	Gene therapy, supportive care
Medication	N/A
Prognosis	Variable
Frequency	N/A
Deaths	N/A

Amaurosis congenita of Leber, type 2 (LCA2) is a rare genetic disorder that results in severe vision loss at birth. It is a form of Leber congenital amaurosis (LCA), which is a group of inherited retinal dystrophies characterized by severe visual impairment in infancy.

Genetics

LCA2 is caused by mutations in the RPE65 gene, which is located on chromosome 1. The RPE65 gene encodes an enzyme that is crucial for the visual cycle, specifically in the conversion of all-trans-retinyl esters to 11-cis-retinol, a key step in the regeneration of rhodopsin in the retina. Mutations in this gene disrupt the visual cycle, leading to the degeneration of photoreceptor cells and subsequent vision loss.

Clinical Presentation

Patients with LCA2 typically present with:

• Severe vision loss or blindness from birth
• Nystagmus (involuntary eye movements)
• Poor pupillary light reflex
• Abnormal electroretinography (ERG) results, indicating severely reduced or absent retinal function

Diagnosis

The diagnosis of LCA2 is based on clinical findings and confirmed by genetic testing. Electroretinography is used to assess retinal function, and genetic testing can identify mutations in the RPE65 gene.

Treatment

The treatment for LCA2 has advanced significantly with the development of gene therapy. The first gene therapy approved for LCA2 is voretigene neparvovec (Luxturna), which delivers a normal copy of the RPE65 gene directly to the retinal cells. This therapy has shown promise in improving vision in patients with LCA2.

Supportive treatments include low vision aids and educational support to help patients adapt to their visual impairment.

Prognosis

The prognosis for individuals with LCA2 varies. While traditional treatments offered limited improvement, gene therapy has provided new hope for enhancing vision and quality of life in affected individuals.

Also see

• Leber congenital amaurosis
• Retinitis pigmentosa
• Gene therapy
• RPE65