Infantile amaurosis
Introduction
Introduction to infantile black Mongolian dementia Infant-type melanotype dementia, namely Bielschowsky syndrome, also known as Bielschowsky-Jansky syndrome, D?llinger-Bielschowsky syndrome, Bernheimer-Seitelberger syndrome, late-onset infantile black senile familial dementia (amauroticfamilialinfantileidiocy), late infant type Wax-like lipofuscinosis, GM2gangliosidosis, juvenile GM2gangliosidosis, etc. This symptom is autosomal recessive. Due to the lack of hexosaminidase or sphingolipidactivator protein, GM2 gangliosides and associated glycosphingolipids are deposited, causing degeneration of the brain. basic knowledge The proportion of sickness: 0.01% Susceptible people: children Mode of infection: non-infectious Complications: convulsion in children, ataxia, macular degeneration, optic atrophy, disturbance of consciousness
Cause
Infant type of black stagnation dementia
Tay-Sachs disease (30%):
This disease is the earliest discovered ganglioside accumulation disease, which is known to be due to the complete or partial lack of activity of the hexaminidase (HEX) hydrolyzing ganglioside GM2 type, so that GM2 cannot be degraded in vivo. Accumulated in (brain, eye, liver, spleen, and bone marrow). According to the classification in recent years, the classic Tay-Sachs disease can occur in the absence of HEX-A type, and the Sandoff disease is another if both types of A and B in HEX are lacking.
Pathogenesis The central nervous system contains a variety of complex lipids, including dozens of gangliosides (complex glycolipids). Their chemical structures are mainly ceramides, which are conjugated to several molecules of hexose (galactose, glucose) and sialic acid (N-acetylneuraminic acid, NANA). . Since the number of NANA contained therein is different, they are named GM (single NANA), GD (two molecules), GT (three molecules), GQ (four molecules), and the like. The substance accumulated in the brain cells of patients with this disease is GM2 containing a single molecule of NANA and three hexose residues, which is degraded from tetrahexosides GM1 by -galactosidase and further degraded to GM3 by HEX. .
The disease is more common in Eastern European Jews, but non-Jewish and non-white children cannot be excluded from the diagnosis.
Diagnosis relies on the determination of aminohexosasease isoenzyme A. There is no special treatment for this disease, usually 3 to 4 years old.
Sandhoff's disease (30%):
The patient lacks hexosaminidase A and B, which not only causes GM2 gangliosides to deposit in the brain, but other -aminohexose final products such as glycolipids, glycoproteins and oligosaccharides are also in the brain. Deposition in the internal organs. The clinical manifestations are similar to Tay-Sachs disease, but there is visceral involvement. The content of GM2 gangliosides in the brain is increased by 100 to 200 times, and the liver, kidney, spleen and erythrocyte glycosides are greatly increased, and in the red blood cells, mainly glycosphingolipids.
Juvenile GM2 gangliosidosis (30%):
(Type III) is caused by a partial deficiency of aminohexosaminidase A, which is later than Tay-Sachs disease and Sandhoff disease. Ataxia and progressive mental retardation development begin at 2 to 6 years of age. Language loss, progressive rigidity, hand and limbs in a Xu-like posture, and the occurrence of small sputum, no organ enlargement, skeletal deformities and vacuolar cells, can be blind in the late stage. Most children die between 5 and 15 years of age.
Prevention
Infant type blindness prevention
Check the activity of hexosamine isoenzyme A in the blood to detect patients and carriers; biochemical analysis of cultured amniotic fluid cells can make prenatal diagnosis. The above method is conducive to preventive work and terminate pregnancy if necessary.
Complication
Infant type black montane dementia complications Complications, convulsions, ataxia, macular degeneration, optic atrophy, dysfunction
There was a serious convulsion. Exercise and mental retardation, vision loss, ataxia, retinal atrophy, macular degeneration, optic atrophy and gradually blind. Small brain deformity. Now the hands and feet are moving and squatting.
Convulsion: Convulsion is a common emergency in children, especially in infants and young children. Cerebral nerve dysfunction caused by a variety of reasons. It is characterized by a sudden systemic or local muscle group with tonicity and clonic convulsions, often accompanied by conscious disturbances. The incidence of convulsions in children is very high. According to statistics, the incidence of convulsions in children under 6 years old is about 10 to 15 times that of adults. About 5 to 6% of children have had one or more convulsions. The reason is: the development of cerebral cortex in infants and young children is not perfect, so the analysis and identification and inhibition function are poor; the myelin sheath is not completely formed, the insulation and protection are poor, after stimulation, the excitatory impulse is easy to generalize; the immune function is low, easy Infection and convulsions; poor blood-brain barrier function, various toxins easily penetrate into brain tissue; some special diseases such as birth injury, brain development defects and congenital metabolic abnormalities are more common, which are the incidence of convulsion in infants and young children High reason. Frequent seizures or persistent states are life-threatening or can leave serious sequelae in children, affecting children's mental development and health.
Ataxia: The normal movement of the human body is the balance and coordination of the movement in the cerebral cortex motor area, the basal nucleus of the cortex, the vestibular labyrinth system, the deep sense and the vision, called the mutual aid movement. The lesions of these structures lead to coordination disorders called ataxia.
Macular degeneration: divided into atrophic and exudative types.
1. Atrophic type - also known as dry or non-exudative, mainly caused by choroidal capillary atrophy, thickening of the glass membrane and atrophy of the macular area caused by atrophy of the retinal pigment epithelium.
2, exudative type - also known as wet or discoid macular degeneration
Mainly for the destruction of the vitreous membrane, the choroidal blood vessels invade the subretinal to form the choroidal neovascularization, and the macular area of the retinal pigment epithelium or the neuroepithelial serous or hemorrhagic discoid detachment eventually becomes a mechanical scar, according to the clinical observation of the atrophic type. Can be converted to exudative type.
Symptom
Infant type of black senile dementia symptoms common symptoms ataxia twitching optic atrophy reflex hyperthyroidism muscle tone reduction light reflex disappearing convulsion dementia
Examine
Examination of infantile black Mongolian dementia
Diagnosis
Diagnosis and diagnosis of infantile black Mongolian dementia
