familial polycythemia
Introduction
Introduction to familial polycythemia Oxygen affinity increases hemoglobin, due to changes in the amino acid composition of hemoglobin, the affinity of hemoglobin for oxygen is increased, oxygen is released to the tissue, and tissue hypoxia causes compensatory polycythemia. This disease is a genetic disease, so it is also called "familial erythrocytosis." disease. basic knowledge The proportion of the disease: the probability of getting the disease in the offspring of this disease is about 5% Susceptible people: no special people Mode of infection: non-infectious Complications: polycystic kidney, renal tuberculosis, kidney cancer
Cause
Causes of familial polycythemia
(1) Causes of the disease
This disease is an autosomal dominant genetic disease. The globin gene mutation causes a change in the amino acid composition of the globin chain. A few patients have no family history, which may be caused by a spontaneous somatic gene mutation in the patient. The clinically seen patients are all heterozygous. State, more than 40 kinds of abnormal hemoglobin with increased oxygen affinity have been found.
(two) pathogenesis
The globin gene mutations that cause this disease are roughly divided into four types:
The C-terminal mutation of the 1 or chain reduces the stability of the hemoglobin deoxygenation structure.
The mutation at the 21 and 2 chain contacts hinders the transition of hemoglobin from the oxygenated state to the deoxygenated state.
Mutations in the binding of the 3 chain to the 2,3-diphosphoglycerate weaken the binding between the two, resulting in increased affinity for oxygen.
4 mutation causes amino acid changes related to heme binding, resulting in a change in the spatial structure of the heme cavity, which is beneficial to the oxygenation structure. The amino acid composition of the globin chain caused by the above various mutations changes, the oxygen affinity of hemoglobin is increased, and the oxygen release to the tissue is reduced. Tissue hypoxia stimulates an increase in erythropoietin, causing an increase in erythrocytes.
Prevention
Familial polycythemia prevention
There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.
Complication
Familial polycythemia complications Complications polycystic kidney and kidney tuberculosis
Symptoms of erythrocytosis are common symptoms such as dizziness, head swelling, headache, fatigue, palpitations, insomnia, glare, sweating, etc. Sometimes angina, dark red to blemishes on the face, fingers, lips and auricles, mucosa and conjunctiva Congestion and vasodilation. Kidney disease secondary erythrocytosis is the most common in renal cancer, followed by polycystic kidney, hydronephrosis, benign renal adenoma, renal sarcoma, kidney tuberculosis, etc. Secondary renal tumors and kidney transplants also have secondary red blood cells. Increased reports.
Symptom
Symptoms of familial polycythemia Symptoms Common symptoms Excited dizziness, bloating, numbness and congestion
Eye combined with membrane, lips, face and limbs at the end of congestion, may have head swelling, dizziness, headache, insomnia, irritability, limb numbness and other symptoms, but most patients with symptoms are not obvious, the spleen is generally not swollen, may occur during pregnancy Or stillbirth.
Examine
Examination of familial polycythemia
Peripheral blood
The hemoglobin concentration can be increased normally or to varying degrees, even up to 238 g/L, hematocrit 0.42 to 0.70, and white blood cell and platelet counts are normal.
2. Hemoglobin electrophoresis
It can show that the partial oxygen affinity increases abnormal hemoglobin migration speed is different from HbA, and an abnormal zone appears. Some abnormal hemoglobin needs to be distinguished from HbA by pH 6.2 buffer or isoelectric focusing electrophoresis, and some abnormalities. Hemoglobin cannot be identified by electrophoresis, and the oxygen affinity (P50 value) needs to be determined to confirm that the oxygen affinity of such abnormal hemoglobin is 4-6 times higher than normal.
According to clinical manifestations, symptoms, signs, ECG, B-ultrasound, X-ray, biochemical examination.
Diagnosis
Diagnosis and diagnosis of familial polycythemia
Patients with polycythemia and family history should consider this disease, hemoglobin electrophoresis found abnormal hemoglobin zone and/or hemoglobin oxygen affinity is significantly increased to confirm the diagnosis, globin chain amino acid composition analysis or globin gene analysis can confirm the disease Molecular pathology.
