Amauroz Leber
The content of the article:
- Causes and risk factors
- Forms of the disease
- Symptoms
- Diagnostics
- Treatment
- Potential consequences and complications
- Forecast
Leber's amaurosis is a genetic ophthalmic disease that leads to a significant deterioration in visual function (up to its complete loss). It is based on irreversible damage to the photosensitive cells of the retina of the eyeball (cones and rods).
Leber's amaurosis belongs to rare hereditary pathologies: it occurs with a frequency of 3 cases for every 100,000 newborns. Approximately every 5th case of congenital blindness or low vision is due to Leber's amaurosis.
Leber's amaurosis is a hereditary retinal disease
Causes and risk factors
Leber's congenital amaurosis is a whole group of retinal dystrophies caused by various genetic causes. Most often it is inherited in an autosomal recessive manner, that is, for the development of pathology, the child must receive a mutated gene from both the mother and the father.
There are several forms of Leber's amaurosis that are inherited in an autosomal dominant manner. In this situation, for the onset of a dystrophic process in the retina of the eyeball, only one changed gene is enough.
Forms of the disease
Depending on the particular gene in which the mutation occurred, several types of the disease are distinguished:
- Mutations in the CRX gene, which is responsible for the development of photoreceptors in the embryo, as well as the maintenance of the required number throughout life. Mutations in it cause late retinal pigment degeneration, type VII Leber amaurosis and rod-cone dystrophy. All these forms of the disease have an autosomal dominant mode of inheritance.
- Mutations in the LCA5 gene, which encodes the synthesis of the protein lebercillin by retinal cells. Its mutations lead to type V Leber amaurosis with an autosomal dominant mode of inheritance.
- Mutations in the RPE gene It carries the code for the synthesis of a protein specific to the retinal pigment epithelium and playing a leading role in the metabolism of retinol. More than 80 variants of the RPE65 gene mutation have been described, which lead to retinal pigment degeneration, Leber type II amaurosis.
- Mutations in the LRAT gene, which is responsible for the synthesis of a microsomal protein - lecithin retinol acyltransferase (LRAT). It is involved in the exchange of retinol (vitamin A) in the cells of the vision and liver. Gene mutations cause pigmentary juvenile degeneration of the retina, type XIV Leber amaurosis.
- Mutations in the CRB1 gene, which encodes the synthesis of a protein necessary for the normal development and functioning of photoreceptors. Currently, more than 140 different mutations of this gene are known, which lead to type XII pigmentary retinal degeneration, type VIII Leber amaurosis.
Symptoms
With Leber's amaurosis, children are born blind or have a rapidly progressive deterioration in vision, leading to complete blindness during the first ten years of life.
It is possible to suspect this disease already in the first months of a child's life based on the following symptoms:
- lack of reaction of the pupil to light;
- lack of fixation of gaze on objects, wandering gaze;
- nystagmus.
Diagnostics
Diagnosis of Leber's amaurosis begins with an ophthalmological examination. Then the following techniques are used:
- visual evoked potentials (VEP);
- electroretinography;
- electrooculography.
When diagnosing Leber's amaurosis, a number of studies are carried out in order to register the bioelectric activity of retinal neurons
Electroretinography (ERG) has the greatest diagnostic value. The method allows registering the bioelectric activity of retinal neurons. In Leber's amaurosis, ERG is not recorded. In congenital blindness caused by other causes (syphilis, rubella, optic nerve atrophy), the ERG shows a normal or subnormal picture.
Treatment
Currently, there is no pathogenetically substantiated treatment for Leber's amaurosis. Research is underway to develop methods of genetic therapy for this pathology.
An important aspect of the treatment of children with Leber's amaurosis is the early start of psychological rehabilitation and pedagogical correction.
Potential consequences and complications
Every second child suffering from Leber's amaurosis has a delay in psychomotor development due to impaired visual function. In addition, muscle hypotonia and decreased motor activity are noted.
Forecast
The prognosis for Leber's amaurosis is negative: children are either irreversibly blind from birth or lose their sight during the first ten years of life.
Elena Minkina Doctor anesthesiologist-resuscitator About the author
Education: graduated from the Tashkent State Medical Institute, specializing in general medicine in 1991. Repeatedly passed refresher courses.
Work experience: anesthesiologist-resuscitator of the city maternity complex, resuscitator of the hemodialysis department.
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
