Leber hereditary optic neuropathy

Introduction to Leber's hereditary optic neuropathy Leber's hereditary optic neuropathy (LHON) is a maternal inheritance or mitochondrial inheritance caused by mutations in the mitochondrial DNA 11778, 14484 or 3460. It is a common type of hereditary optic neuropathy. basic knowledge The proportion of illness: 0.02% Susceptible people: no special people Mode of infection: non-infectious Complications: optic atrophy Posterior optic neuritis

Causes of Leber's hereditary optic neuropathy

Causes:

At present, the site mutation of mitochondrial DNA is considered to be a specific symptom of LHON. 25 site mutations have been reported in foreign countries. It is generally accepted that the primary mutation site has 11778 (GA) accounted for 40%, and 3460 (GA) accounted for 6% to 25% and 14484 (TC) accounted for 10% to 15% of 3, which can cause disease alone, not found in the normal population. In 1991, Huoponen et al first found 3460 mutations in the N41 gene, the following year 1992. In the year of John et al., 14484 mutations were found. The LHON11778 mutation in China accounted for 66%, but it is rare. It is believed that the site mutation is closely related to LHON. A few 4146 and 14459 mutations are considered to be the main pathogenic diseases associated with LHON. Sexual mutation.

Pathogenesis:

LHON secondary sites have increased in recent years, reaching 22, although their incidence in LHON patients is higher than in the control group, but also in the control family, it is generally considered to be polymorphism, the mother found differences It is qualitative and does not suffer from disease when it exists alone. Some people think that the secondary site can not change the performance of the disease, but some people think that it can enhance the possibility of phenotypic expression, which may play a mediating role or have a low risk.

Leber hereditary optic neuropathy prevention

prevention:

Smoking cessation and alcohol withdrawal may be effective. For women who have been confirmed as female carriers, prenatal examination should be performed. Breakline Leber Hereditary Optic Neuropathy Western Medicine Treatment: There is no effective treatment for this disease. Because some patients can naturally recover their vision during the course of their illness, any treatment effect should be evaluated with caution. The disease is currently being considered as one of the key research targets for gene therapy.

Leber hereditary optic neuropathy complications Complications optic atrophy posterior optic neuritis

More development of optic atrophy, also seen acute posterior optic neuritis.

Leber hereditary optic neuropathy symptoms common symptoms visual field reduction visual impairment deafness cerebellar ataxia single eye suddenly appeared... nystagmus dysfunction dystonia migraine dysmotility mental retardation

The genetic commonality of the disease is maternal inheritance and tends to male morbidity. Clinically, it can be divided into preclinical, acute and subacute phases, chronic atrophic period, which is characterized by painless optic neuropathy. The acute visual acuity can be drastically reduced to the index only. Although the visual acuity decreased to a different extent, most (98%) were around 0.1, and there were few blind people. The spontaneous visual recovery may exist, especially in childhood, and it is related to different site mutations. The optic disc is congested. There are telangiectasia and nerve fiber swelling. The retinal arteries and veins are distorted and dilated in different degrees. There are various types of visual field abnormalities. The central dark spots and the paracentral dark spots are the most common. The color vision disorders are acquired acquired, the condition is improved, and the color vision disorder Also improved, often more common in red and green blindness, for those who have not developed in the family, such as examination of color vision disorder, although there is no change in visual acuity should be followed up, LHON early is retinal involvement, followed by optic neuropathy, known as optic nerve network Neuroretinopathy, VEP examination helps to understand the status of visual function, and has a special diagnostic price for subclinical or occult cases. .

1. Dominant optic atrophy is rare. It is an abiotrophy of the optic nerve. It occurs mostly before the age of 10, and most of them have moderate vision in both eyes at 4 to 6 years old. About 40% of patients have a visual acuity of more than 0.3, and only 15% of visual acuity is heavier than below 0.1. According to statistics, there is no visual loss to manual and light perception.

The external eye and the anterior segment of the eye are normal. The fundus is slightly pale on the temporal side of the optic disc. A few visually impaired eyes may be accompanied by nystagmus. The visual field examination can be found in the center, the side center or the dumbbell-shaped dark spot, and the white surrounding vision is normal, but The patient has blue blindness, so the blue field of view is smaller than the red field of view. Using the graphic and flash VEP examination, the patient's VEP amplitude is low and the peak latency is prolonged.

2. Recessive optic atrophy (recessive optic atrophy) is more rare, mostly after birth or 3 to 4 years old, so it is also known as congenital recessive hereditary optic atrophy, more than half of the patients have blood relationship The patient's vision is often severely damaged or completely blind, and there is nystagmus. If the visual field can be checked, the visual field is reduced and the central point is dark. The fundus shows atrophy of the optic nerve, and the depression and retinal blood vessels become thinner. Therefore, sometimes it is easy to be with the blanket. Retinal degeneration is confused, but ERG can be identified: ERG is normal in this disease, and ERG is extinguished in blanket retinal degeneration.

Members of the LHON family may exhibit other neurological abnormalities such as peripheral neuropathy, headache, migraine, mental retardation, tremor, epilepsy, deafness, spinal column involvement, cerebellar ataxia, movement disorders, dystonia, bladder weakness Others still have cardiac conduction disorders, which occur at 11778 mutations; 3460 mutations are predisposed to pre-excitation syndrome, and there are reports of demyelinating diseases similar to multiple sclerosis in LHON family. Symptoms and signs consistent with multiple sclerosis (MS) can be seen in the presence of optic neuropathy. Cerebrospinal fluid and magnetic resonance imaging in these patients can be found in typical manifestations of multiple sclerosis, and mtDNA in patients with multiple sclerosis is not shown in the population survey. The incidence of mutations has increased. It seems that the two diseases are not necessarily related, but they can be combined. If MS patients have LHON site mutations, the prognosis of optic neuritis will be worse. Some patients with severe neurological system are still seen. Abnormal LHON, known as Leber syndrome, such as optic neuropathy still has motor disorders, paralysis, mental disorders, skeletal muscle abnormalities, urgency Baby onset of encephalopathy.

Some people think that the disease is caused by changes in the retinal blood vessels and is called "telangiectasia microangiopathy". This microvascular disease can occur before the onset of the disease. Therefore, members of the family should carefully follow the fundus examination. Smith believes that early There may be vascular dilatation of the arteriolar vessels around the optic disc, swelling of the retinal nerve fiber layer around the optic disc and no leakage of the optic disc, and the chronic phase is gradually pale or even pale.

The diagnosis was mainly based on medical history, clinical manifestations, and mtDNA laboratory test results.

Leber hereditary optic neuropathy

1. PCR-SSCP analysis: It is a simple and sensitive screening method for detecting mutations or mutations in mtDNA fragments, and there are many improved methods. It is easier to perform mtDNA molecular genetic testing on LHON with clear history. A positive result is obtained, and the generation of the MaeIII recognition endpoint improves the diagnostic accuracy and avoids false positives or false negatives.

2. Cerebrospinal fluid immunoglobulin and cytology examination.

3. Fundus fluorescein angiography (FFA) In the acute phase, the optic disc is strongly fluorescent, the blood vessels are highly dilated, the optic disc of the optic disc is filled with capillaries, and the defects are delayed. FFA examination can detect patients and carriers with possible onset, so it can be used for genetics. Consultation, for asymptomatic and slight vascular changes, may occur in a few years.

4. Brain evoked potential (EPS) and cranial CT, MRI examination of some cases can be found consistent with multiple sclerosis.

5. Electroretinogram (ERG) examination: Can be used for differential diagnosis.

Diagnosis and differentiation of Leber hereditary optic neuropathy

Where the age is greater than 40 years, the visual acuity suddenly drops, and the visual field defect is not positive, the possibility of ischemic optic neuropathy should be considered. However, it is necessary to exclude oppressive optic neuropathy, demyelinating diseases and hereditary diseases.

The diagnosis of anterior ischemic optic neuropathy can be based on:

1 sudden drop in vision, typical visual field defect;

2 headache, eye marks, especially caused by temporal arteritis;

3 optic disc is grayish white edema;

4 fundus fluorescein angiography shows that the optic disc has low fluorescence or fluorescent filling is slow or not filling;

5 hands and feet have Raynaud phenomenon;

The eye pressure recovery rate of the 6 eye compression test was significantly lower.

The diagnosis of posterior ischemic optic neuropathy can be based on:

1 sudden drop in vision and visual field defect;

2 no headache, eye pain;

3 the fundus is normal or the nasal side of the optic disc is slightly light, and the boundary is clear;

4 older than 40 years old, often have high blood pressure, low blood pressure, arteriosclerosis or changes in blood composition; less than 40 years old Raynaud phenomenon, or history of trauma or panic.

It should be pointed out that the clinical diagnosis of posterior ischemic optic neuropathy is often difficult, and most of them are presumed to be difficult to distinguish from posterior optic neuritis. Some people think that abnormal ocular flow pattern or cerebral infarction confirmed by head CT can be used as a reference.

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