Hemoglobin C disease
Introduction
Introduction to hemoglobin C disease Hemoglobin C disease is also caused by a point mutation in the globin gene, a certain amino acid in the -globin chain is replaced by another amino acid, causing a disease caused by changes in the properties and functions of hemoglobin, and hemoglobin C is a -globin gene. An abnormal hemoglobin that is mutated to replace glutamate at the 6th position of the -globin chain with lysine. basic knowledge The proportion of illness: 0.15% Susceptible people: no special people Mode of infection: non-infectious Complications: cholelithiasis splenomegaly
Cause
Hemoglobin C disease etiology
(1) Causes of the disease
HbC disease is autosomal dominant.
(two) pathogenesis
HbC has low oxygen affinity, and it is easy to form crystals in red blood cells after oxidation. The red blood cells containing crystals are stiff and deformed, and it is not easy to lose some cell membranes during microcirculation, so that red blood cells become small spherical red blood cells, and small spherical red blood cells have low deformability. It is easily destroyed by phagocytosis of the mononuclear phagocytic system (hepatic spleen, etc.), resulting in hemolytic anemia.
The disease is divided into 3 types: the patient inherits an abnormal gene (6) from both parents, and forms a homozygous state, which is called HbC disease. For example, the patient inherits an abnormal gene (6) from both parents. A normal gene is a heterozygous state, called HbC trait. If a patient inherits one HbC gene from a parent (6 Valley Lai), and inherits one sickle cell gene (6 Valley) from the other side. There are HbC and HbS double heterozygous state, forming sickle cell HbC disease.
Prevention
Hemoglobin C disease prevention
Mainly pay attention to the usual life, mainly to prevent, early detection and early treatment.
Complication
Hemoglobin C disease complications Complications cholelithiasis splenomegaly
1. Long-term continuous hemolysis can be combined with cholelithiasis and splenomegaly.
2. Sickle HbC disease can be complicated by embolism symptoms and signs, of which eye complications are common.
Symptom
Hemoglobin C disease symptoms Common symptoms Abdominal pain jaundice fatigue dizziness tinnitus joint pain
Patients may have no symptoms. Some patients have very short abdominal pain and joint pain. They may have fatigue, dizziness, tinnitus, jaundice and other manifestations due to hemolytic anemia. The mortality rate of sickle-like HbC disease is about 10%. Some patients from children Moderate anemia began in the period of puberty or puberty. Growth and development were mostly normal, and half of the patients had mild splenomegaly.
Examine
Examination of hemoglobin C disease
1. Peripheral blood HbC disease, Hb 80 ~ 120g / L, MCV average is about 72fl, the target red blood cells in the blood tablets increased significantly, about 30% ~ 100%, reticulocytes increased, about 4% ~ 8%, generally Not more than 10%, Hb C traits, normal hemoglobin, no increase in reticulocytes, target red blood cells 10% to 50%, red blood cell osmotic fragility significantly reduced, sickle cell HbC disease, hemoglobin slightly decreased, MCV and MCHC decreased.
2. Red blood cell survival time is shortened, 51Cr t1/2 16 to 20 days.
3. Bone marrow is markedly hyperplasia of erythroid cells, white blood cell system, and megakaryocytes are normal.
4. Hemoglobin electrophoresis shows that almost all hemoglobin is HbC, HbF is slightly increased, no HbA, hemoglobin C traits: hemoglobin electrophoresis shows that HbC accounts for 28% to 44%, HbA2 is slightly increased, and the rest is HbA, sickle cell HbC disease: Hemoglobin electrophoresis showed that HbC and HbS were present at the same time, no HbA, added to the washed red blood cell slides in 3% sodium citrate solution, covered with coverslips, sealed, and more red blood cells were observed after several hours at room temperature. There is crystal inside.
According to clinical manifestations, symptoms, signs to choose to do B-ultrasound, X-ray, ECG, biochemistry and other tests.
Diagnosis
Diagnosis and identification of hemoglobin C disease
According to clinical manifestations, peripheral blood tests, especially hemoglobin electrophoresis, can make a correct diagnosis.
Generally, no identification is required, but when using a pH 8.8 TEB buffer for starch gel electrophoresis, HbC has the same electrophoresis position as HbA2, HbE and HbOArab, such as HbC with a phosphate or citrate buffer agar electrophoresis at pH 6.25. The other three hemoglobin positions are different and can be identified.
