Overview.
Bone marrow-pancreas syndrome, also known as Pearson syndrome, is a mitochondrial disorder with congenital progressive multisystem damage due to major deletions (or rearrangements) of mitochondrial DNA.
Etiology
Autosomal dominant inheritance of erythrocyte enzyme defects due to major deficiencies or rearrangements of mitochondrial DNA.
Symptoms
Clinical features include, in addition to anemia noted shortly after birth, pancreatic exocrine insufficiency, increased lactate levels, occasional lactic acidosis, and eventually liver and kidney failure. Based on the characteristics of the disease, it is generally not difficult to make a diagnosis of iron granulocytic anemia. However, it needs to be differentiated from idiopathic, i.e., secondary, iron granulocytic anemia.
Examination
1. Peripheral blood
Decreased hemoglobin, the characteristics of hypochromic anemia are obvious, blood smear erythrocyte morphology is often bi-directional, i.e., the morphology can be seen as normal and abnormal two types of cells. Red blood cells are markedly heterogeneous in size; anomalous, target-shaped, elliptical, and spot-colored red blood cells are increased. Reticulocyte count is decreased. The white blood cell count and platelet count are decreased. The osmotic fragility of erythrocytes is markedly inconsistent and may be increased or decreased.
2. Bone marrow
The red lineage cells in the bone marrow are hyperproliferative, and iron staining shows a significant increase in ferritin-containing cells, an increase in ferritic granulocytes to 80% to 90%, and 10% to 40% of cyclic ferritic granulocytes, most of which are middle- and late-stage erythrocytes. Iron granulocytes can also be found in blood smears. Occasionally, megaloblastic erythrocytes appear, which may be associated with folic acid deficiency.
3. Serum iron
Most of the serum iron is increased, and iron saturation is often increased significantly. Iron kinetic studies usually show that plasma iron clearance is accelerated, which is 1/4～1/2 of normal; iron utilization rate is reduced, which is 1/5～1/3 of normal.
4. Liver biopsy
Liver biopsy shows iron deposition, and the liver of non-transfused patients may have the same changes, often accompanied by asymptomatic nodular cirrhosis, which is very similar to the liver lesions of hereditary hemochromatosis.
5. Metabolic abnormalities
In some patients, when the tryptophan load is aggravated, the urinary excretion of xanthuric acid (4,8-dihydroxyquinolinecarboxylic acid) and/or kynurenic acid increases, suggesting that the metabolism of tryptophan is abnormal.
6.Other
Electrocardiogram, ultrasound, X-ray and other tests are selected according to the condition, clinical manifestations, symptoms and signs.
Diagnosis
According to the characteristics of the disease, it is generally not difficult to make the diagnosis of iron granulocytic anemia. However, it needs to be differentiated from idiopathic, i.e., secondary, iron granulocytic anemia. Therefore, it must be considered on the basis of a detailed history and physical examination, as well as a family history.
Differential Diagnosis
The disease needs to be differentiated from thalassemia. Thalassemia may be associated with ferroblastic anemia. Due to a significant reduction in the synthesis of pearl proteins, excess hemoglobin can feedback to inhibit the enzyme ALA synthase, leading to ferrocytic anemia.
Treatment.
There is a lack of effective treatment for this disease.
Prognosis
The prognosis is poor. Survival is longer in less severe lesions, and recovery of anemia has been reported in survivors over 20 years of age.