ataxia telangiectasia type 1 syndrome in children
Introduction
Introduction to pediatric ataxia telangiectasia type I syndrome Ataxia telangiectasia type I syndrome (ataxiatelangiectasiasyndrome), also known as ataxia telangiectasia, ataxia telangiectasia immunodeficiency (immunodeficiency withataxiatelangiectasia), Louis-Bar syndrome, Boder-Sedgwick syndrome, etc. Congenital defects of skin, eye, nervous system symptoms and antibody immune function are characteristic of this disease. It is a chronic disease characterized by progressive cerebellar ataxia, ocular and facial telangiectasia and recurrent respiratory infections. . Autosomal recessive inheritance, more women than men. basic knowledge The proportion of sickness: 0.01% Susceptible people: children Mode of infection: non-infectious Complications: malignant lymphoma leukemia
Cause
Pediatric ataxia telangiectasia type I syndrome etiology
(1) Causes of the disease
This disease is an autosomal recessive genetic disease.
(two) pathogenesis
Mainly due to DNA repair defects, about 1/4 of patients with lymphocytes on chromosome 14 have short breaks on the short arm, 14q12, and it is not yet possible to explain the multiple systemic damages such as nerve, blood vessel and immunological abnormalities in the sick child. It is speculated that it may be Defects in germ layer development, some people believe that the basic defects are abnormalities of the immune system, especially thymic defects, which can lead to viral infection or autoimmunity, which is secondary to multiple systemic damage. Central nervous system damage, such as demyelination and degeneration, also suggests It is an autoimmune process, but the mechanism that causes immunological abnormalities is not clear.
The most prominent changes in this disease are thymic developmental disorders, incomplete lymphoid system, skin telangiectasia, gonadal developmental disorders, cerebellar cortical atrophy, olive degeneration, brain stem and spinal cord posterior horn and anterior horn degeneration and atrophy.
Skin pathological examination showed significant expansion of small blood vessels.
Prevention
Pediatric ataxia telangiectasia type I syndrome prevention
Pregnant woman health care
It is known that the occurrence of some immunodeficiency diseases is closely related to embryonic dysplasia. If pregnant women are exposed to radiation, receive certain chemical drugs or have a viral infection (especially rubella virus infection), they can damage the fetal immune system, especially It is in the early pregnancy that can involve multiple systems including the immune system. Therefore, it is very important to strengthen the health care of pregnant women, especially in the early pregnancy. Pregnant women should avoid receiving radiation, use some chemical drugs to inject rubella vaccine, etc., to prevent viral infection as much as possible, and to strengthen the nutrition of pregnant women, and timely treat some chronic diseases.
2. Genetic counseling and family survey
Genetic counseling for family history can help affected adults to have selective fertility. Non-patients in the patient's family can be properly married.
3. Prenatal diagnosis includes regular ultrasound examination, serological screening, etc., if necessary, chromosome examination, congenital diagnosis and heterozygous screening.
Early and accurate diagnosis of ataxia telangiectasia syndrome, early administration of specific treatment and provision of genetic counseling (prenatal diagnosis or even intrauterine treatment) are very important.
Complication
Pediatric ataxia telangiectasia type I syndrome complications Complications, malignant lymphoma, leukemia
Can not walk, mostly from childhood sinusitis, otitis media or pneumonia, sometimes with chronic diarrhea, can be "dwarf", skin malignant lesions, repeated respiratory infections are often fatal factors, sinus-pulmonary infection, bronchiectasis, second Delayed or undeveloped sexual characteristics, testicular atrophy, malignant lymphoma and leukemia can occur.
Symptom
Pediatric ataxia telangiectasia type I syndrome symptoms common symptoms ataxia immunodeficiency recurrent infection lung infection intentional tremor pigmentation eczema strabismus testicular atrophy menstrual cycle changes
Progressive cerebellar degeneration, eye conjunctiva and skin telangiectasia and infection tend to be the three main symptoms of this symptom, and the initial symptoms may vary.
Ataxia
Most of the sick children develop ataxia when they start walking, and some occur when they are 4 to 6 years old. When they are walking, they have symptoms such as limb and trunk movement ataxia, intentional tremor, cerebellar dysarthria and other cerebellar symptoms. Often there are nystagmus and eye movements that can't or strabismus, 30% of children have mental retardation, the face is characterized by "low tension" and sluggish performance, growth retardation, can be "dwarf", some children may also have Extrapyramidal symptoms.
2. Capillary expansion
Capillary vasodilation can occur as early as 1 year old or as late as 9 years old, often first manifested in the bulbar conjunctiva, and later in the ear, anterior elbow fossa, nasal bridge, back of the hand and back of the foot, other skin lesions have skin atrophy, hard skin, pigmentation Loss or stagnation, atopic dermatitis, eczema and malignant lesions of the skin.
3. Repeated infection
Among these children, this is the earliest abnormal manifestation. Immunodeficiency is an important feature of this disease. Serum IgA is decreased, IgM is normal, 60%-80% of children have a tendency to get infected, and respiratory infection is often a lethal factor, about 75%. The case was sinus-pulmonary infection with bronchiectasis and eventually pneumonia.
4. Other
If the patient lives to adolescence, the appearance of secondary sexual characteristics can be significantly delayed or even completely undeveloped. Although female patients may have menstruation, but irregular, or even eventually stop completely, male patients may have testicular atrophy, about 10% Lymphatic reticular system malignant disease can occur in sick children. Gatti et al. In 1971, the malignant tumors of this disease were found to be malignant lymphoma and leukemia, and other gliomas, gastric cancer, undifferentiated cell tumors, and the like.
Examine
Examination of pediatric ataxia telangiectasia type I syndrome
Its humoral and cellular immune system abnormalities, immunoglobulin decreased, about 70% of children with IgA, IgE decreased or lacked, small lymphocytes decreased, sometimes all immunoglobulins were low, tuberculin test, dinitro Chlorobenzene (DNCB) spot test, skin grafts and other delayed response allergic reactions such as decreased reaction, decreased lymphocyte transformation rate, etc., it was found that the peripheral blood lymphocytes decreased in children, and some people think that the blood circulation of such children The number of -lymphocytes with IgA and the absolute number of T lymphocytes are normal, so the number of lymphocytes in the blood can be unaffected.
Pathological anatomy can be found that the thymus is small and has histological changes.
X-ray chest radiographs are small in the thymus, inflammatory infiltrates can be seen in the lung infection, bronchiectasis can be seen, B-ultrasound and EEG are checked if necessary.
Diagnosis
Diagnosis and differential diagnosis of pediatric ataxia telangiectasia type I syndrome
diagnosis
According to the clinical manifestations of the symptoms and laboratory tests, abnormalities in body fluids and cellular immunity, such as elevated IgM, decreased IgG or decreased Ig, decreased peripheral blood lymphocyte count, normal or decreased T lymphocyte percentage, and distal The absolute number of blood lymphocytes is reduced, and the cells are easily destroyed during culture. This is a characteristic of the disease. The skin test of delayed type hypersensitivity is weakened or negative, and laboratory tests such as decreased lymphocyte transformation rate can be diagnosed.
Differential diagnosis
Identification of immunodeficiency diseases, the characteristics of progressive cerebellar ataxia and telangiectasia can help identify.
