A myelodysplastic syndrome (MDS) is one of a group of cancers in which immature blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms typically are seen. Later, symptoms may include fatigue, shortness of breath, bleeding disorders, anemia, or frequent infections. Some types may develop into acute myeloid leukemia.
In hematology, thrombocytopenia is a condition characterized by abnormally low levels of platelets in the blood. Low levels of platelets in turn may lead to prolonged or excessive bleeding. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients and a third of surgical patients.
Megaloblastic anemia is a type of macrocytic anemia. An anemia is a red blood cell defect that can lead to an undersupply of oxygen. Megaloblastic anemia results from inhibition of DNA synthesis during red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. This leads to continuing cell growth without division, which presents as macrocytosis. Megaloblastic anemia has a rather slow onset, especially when compared to that of other anemias. The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically vitamin B12 deficiency or folate deficiency. Loss of micronutrients may also be a cause.
Macrocytosis is a condition where red blood cells are larger than normal. These enlarged cells, also known as macrocytes, are defined by a mean corpuscular volume (MCV) that exceeds the upper reference range established by the laboratory and hematology analyzer. Upon examination of a peripheral blood smear under microscope, these macrocytes appear larger than standard erythrocytes. It’s noteworthy that macrocytosis is a common morphological feature in neonatal peripheral blood. The presence of macrocytosis can indicate a range of conditions, from benign, treatable illnesses to more serious underlying disorders.
Sideroblastic anemia, or sideroachrestic anemia, is a form of anemia in which the bone marrow produces ringed sideroblasts rather than healthy red blood cells (erythrocytes). In sideroblastic anemia, the body has iron available but cannot incorporate it into hemoglobin, which red blood cells need in order to transport oxygen efficiently. The disorder may be caused either by a genetic disorder or indirectly as part of myelodysplastic syndrome, which can develop into hematological malignancies.
GATA-binding factor 1 or GATA-1 is the founding member of the GATA family of transcription factors. This protein is widely expressed throughout vertebrate species. In humans and mice, it is encoded by the GATA1 and Gata1 genes, respectively. These genes are located on the X chromosome in both species.
Reticulocytopenia is the medical term for an abnormal decrease in circulating red blood cell precursors (reticulocytes) that can lead to anemia due to resulting low red blood cell (erythrocyte) production. Reticulocytopenia may be an isolated finding or it may not be associated with abnormalities in other hematopoietic cell lineages such as those that produce white blood cells (leukocytes) or platelets (thrombocytes), a decrease in all three of these lineages is referred to as pancytopenia.
Chronic recurrent multifocal osteomyelitis (CRMO) is a rare condition (1:1,000,000), in which the bones have lesions, inflammation, and pain. It is called multifocal because it can appear in different parts of the body, primarily bones, and osteomyelitis because it is very similar to that disease, although CRMO appears to be without any infection.
Hematologic diseases are disorders which primarily affect the blood and blood-forming organs. Hematologic diseases include rare genetic disorders, anemia, HIV, sickle cell disease and complications from chemotherapy or transfusions.
Congenital hemolytic anemia (CHA) is a diverse group of rare hereditary conditions marked by decreased life expectancy and premature removal of erythrocytes from blood flow. Defects in erythrocyte membrane proteins and red cell enzyme metabolism, as well as changes at the level of erythrocyte precursors, lead to impaired bone marrow erythropoiesis. CAH is distinguished by variable anemia, chronic extravascular hemolysis, decreased erythrocyte life span, splenomegaly, jaundice, biliary lithiasis, and iron overload. Immune-mediated mechanisms may play a role in the pathogenesis of these uncommon diseases, despite the paucity of data regarding the immune system's involvement in CHAs.
Congenital hypoplastic anemia is a congenital disorder that occasionally also includes leukopenia and thrombocytopenia and is characterized by deficiencies of red cell precursors.
Congenital dyserythropoietic anemia (CDA) is a rare blood disorder, similar to the thalassemias. CDA is one of many types of anemia, characterized by ineffective erythropoiesis, and resulting from a decrease in the number of red blood cells (RBCs) in the body and a less than normal quantity of hemoglobin in the blood. CDA may be transmitted by both parents autosomal recessively or dominantly.
Ineffective erythropoiesis is defined by the expansion of early-stage erythroid precursors driven by erythropoietin, accompanied by the apoptosis of late-stage precursors. This mechanism is principally responsible for the anemia seen in acquired conditions such as certain subtypes of myelodysplastic syndrome (MDS) and inherited disorders such as β-thalassemia, inherited sideroblastic anemias, as well as congenital dyserythropoietic anemias.
Congenital dyserythropoietic anemia type I is a disorder of blood cell production, particularly of the production of erythroblasts, which are the precursors of the red blood cells (RBCs).
Congenital dyserythropoietic anemia type II, or hereditary erythroblastic multinuclearity with positive acidified serum lysis test (HEMPAS) is a rare genetic anemia in humans characterized by hereditary erythroblastic multinuclearity with positive acidified serum lysis test.
Congenital dyserythropoietic anemia type III is a rare autosomal dominant disorder characterized by macrocytic anemia, bone marrow erythroid hyperplasia and giant multinucleate erythroblasts. New evidence suggests that this may be passed on recessively as well.
Congenital dyserythropoietic anemia type IV has been described with typical morphologic features of CDA II but a negative acidified-serum test.
Hemolytic jaundice, also known as prehepatic jaundice, is a type of jaundice arising from hemolysis or excessive destruction of red blood cells, when the byproduct bilirubin is not excreted by the hepatic cells quickly enough. Unless the patient is concurrently affected by hepatic dysfunctions or is experiencing hepatocellular damage, the liver does not contribute to this type of jaundice.
