Diggeorg syndrome
Introduction
Introduction to Digolger Syndrome Children with immunodeficiency syndrome caused by primary T cell immunodeficiency are mainly cell-mediated immunosuppression, accounting for 5% to 20% of primary immunodeficiency diseases, and T cell defects are also indirect. Effector cells that are activated by antigen-initiated T cells, such as monocyte macrophages and B cells. Severe T cell defects produce clinical signs more than one year after birth, which can be manifested as combined immunodeficiency of different immune response systems. Mild T cell defects can be delayed until adulthood, including thymic hypoplasia, hypocalcemia, Congenital heart disease and facial deformity. Most cases are part of Digolger syndrome, which means that the thymus is not damaged, the number and function of T cells are normal, and there are few concurrent infections. A small number of cases are complete Digeorg syndrome, which refers to thymic defects. Some of the thymic defects are also partial, and their immune function defects gradually improve over time. The number and function of T cells in patients with complete Digeorg syndrome are significantly decreased, with a clear tendency to infection. basic knowledge The proportion of illness: 0.005% Susceptible people: children Mode of infection: non-infectious Complications: thyroiditis
Cause
The cause of Digeorg syndrome
(1) Causes of the disease
The disease is caused by some factors (such as viral infection, poisoning) leading to the development of the third and fourth pharyngeal sac neural crest in early pregnancy, causing thymus (often accompanied by parathyroid gland) hypoplasia or non-development, often accompanied by cardiovascular, maxillofacial Department, ear and other developmental malformations, prone to occur in children born to older parents, some children suggest a defect associated with chromosome 22q11, mainly the loss of 22q11.2 (del22q11).
(two) pathogenesis
DGS is a group of multi-deformed complexes including pharyngeal arch, which has complex etiology. Possible factors include contact-induced malformation and maternal diabetes. Most patients with DGS (90%) and cardiac malformations have gene deletion, high-risk mutation or transduction in 22q11. The gene fragment is between D22S75 (N25) and GM00980, and its length is 200-300 kb. The frequently mutated region is between D22S427 and D22S36, and the other susceptible region is the distal end of FCF2. Candidate mutated genes, including NSCR/LAN/IDD, citrate transporter gene (CTP) and DGCR6, are not yet known.
DGS also has other chromosomal site abnormalities, including haploid 10q13, 18q21 and 17p13, 9q diploid and homologous chromosome 18q.
Prevention
Digeorg syndrome prevention
1. Maternal 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 treatments or have viral infections (especially rubella virus infection), they can damage the fetus. The immune system.
2. Genetic counseling and family surveys Although most diseases cannot determine the genetic pattern, it is valuable to conduct genetic counseling for diseases in which genetic patterns have been identified. If adults have hereditary immunodeficiency diseases, they will provide the developmental risks of their children; If a child has an autosomal recessive or sexually linked immunodeficiency disease, tell parents that they are more likely to have a disease in their next child. For immediate family members of patients with antibodies or complement deficiency, antibodies and complement should be examined. Level to determine the family's disease pattern. For some diseases that can be genetically mapped, such as chronic granulomatosis, parents, siblings and their children should be tested for localization. If a patient is found, it should be in him. The family members of her) are examined and the child's children should be carefully observed at the beginning of their birth for any disease.
Complication
Digeorg syndrome complications Complications thyroiditis
Can be complicated by hand and foot convulsions, repeated serious infections, weak and not easy to survive; may have neuropsychiatric development and cognitive impairment, progressive muscle rigidity, gait instability; autoimmune diseases, such as juvenile rheumatoid arthritis , autoimmune hemolytic anemia and thyroiditis.
Symptom
Symigal Syndrome Symptoms Common Symptoms Hypoparathyroidism Decreased Aortic Arch Right Laryngeal Short Nasal Splitting Stator Dysplasia Jaw Small Thymus Defects Aortic Arch Distortion
Due to fetal hypoparathyroidism and hypocalcemia, neonatal hand and foot spasm, hypocalcemia tends to relieve within 1 year after birth, children with special faces, such as wide eyelid distance, low ear position and Incision, the medial longitudinal sulcus of the upper lip is short, the jaw is small and the nose is cracked. There are often large vascular abnormalities, such as tetralogy of Fallot and right aortic arch. If the newborn is not dead, it can occur in 3 to 4 months after birth. Severe viruses, fungi such as Candida and Pneumocystis carinii infection, and bacterial infections are light, vaccination such as vaccinia vaccine, measles vaccine and other live attenuated virus vaccines and bacterial live vaccines such as BCG are susceptible to serious reactions Even death, which is caused by loss of cellular immune function.
Examine
Digolger syndrome check
1. Electrolyte and hormone testing can be found in serum low calcium and high phosphorus, hypothyroid hormone decreased or lack.
2. Immune function test Among the 18 cases of cardiac surgery, only 3 cases can see the thymus in the mediastinum.
(1) Incomplete DGS: There is residual thymus tissue, T lymphocyte proliferative response is normal, T11 cell function is significantly reduced, the number of lymphocytes at birth is 500-1500/mm3, and the normal range is reached at 1 year old, and the number of B cells is normal. Even more, there may be high IgGemia, high antibody response and autoantibodies. It is also reported that the affinity and persistence of the antibody response to the vaccine is not as good as that of normal children of the same age.
(2) Complete DGS: The presence or absence of residual thymus tissue is not a criterion for determining complete DGS, and the defect of T cell proliferative response can be considered as complete DGS. As the age increases, the increase in the number of T cells does not improve the proliferative response. The number of NK cells is also reduced, the number and function of damage are consistent with the degree of damage of T cells, the number of B cells is increased, immunoglobulin can be increased or decreased, IgA deficiency and anti-diphtheria-tetanus toxoid specificity The antibody is low.
3. Prenatal diagnosis and clear disease carriers DGS patients have 50% chance of transmitting the disease to offspring. The chromosome analysis of amniotic fluid cells or chorionic cells found that 22q11 deficiency can make prenatal diagnosis, parents have congenital heart disease or have Diagnosed as 22q11 missing, is the focus of prenatal examination, prenatal ultrasound examination can find heart malformation, although the first child is DGS children, rarely seen the second child, but should still be prenatal examination .
4. Imaging examination: radiological examination of the chest may suggest no thymography, but this does not completely represent the abnormality of T cells. X-ray shows abnormalities of the heart and large blood vessels, such as right arterial arch, pulmonary artery dilatation and heart enlargement, etc. In some cases, the cerebellar vermis and posterior cranial fossa become smaller and small cysts are formed near the anterior horn. Echocardiography can confirm the type of cardiac malformation. Prenatal ultrasound examination can detect cardiac malformations. Brain CT, EEG and cardiovascular should be performed. Contrast examination.
Diagnosis
Diagnosis and diagnosis of Digeorg syndrome
According to the corresponding clinical manifestations of the disease, laboratory and X-ray examination, found that thymus deficiency, parathyroid gland and T cell dysfunction, etc., can diagnose the disease, in which hypoparathyroidism is low, T cell dysfunction is essential Conditions, other performance may or may not be diagnosed.
Different from other primary, secondary immunodeficiency diseases, according to clinical characteristics and laboratory-assisted examination can help identify.
