25-hydroxy vitamin D: screening test to monitor vitamin D level

Aplastic crisis: the production of new red blood cells temporarily stops completely, characterized by an abnormal reduction of reticulocytes in one’s body. It is commonly caused by parvovirus B19.

ATP:  adenosine triphosphate; a high-energy molecule made by glycolysis, which red blood cells use for energy.

Autosomal recessive:  a pattern of inheritance in genetic disorders that means the gene in question is located on non-sex chromosomes (autosomal) and two copies of the mutated gene (one from each parent) are required to cause the disorder (recessive).

Bilirubin: a yellow-orange substance released from red blood cells when they break down, which causes a yellow tinge to skin and the whites of eyes.

Cardiac T2* mapping:  is a noninvasive MRI method that is used to identify myocardial iron accumulation in iron storage diseases.

Chelation therapy:  drugs that remove excess iron from the blood by binding with the iron to form substances that can be excreted from the body easily.

Cholecystectomy: surgical removal of the gallbladder.

Cirrhosis: scarring of the liver that prevents the liver from functioning.

Dual-energy x-ray absorptiometry (DEXA):  a bone density scan, of low-dose x-ray, that measures calcium and other minerals in bone to show strength and thickness of bone.

Dyserythropoietic anemia: anemias resulting from abnormal red blood cell formation such as beta-thalassemia, congenital dyserythropoietic anemia, pyruvate kinase deficiency, hereditary pyropoikilocytosis, and more.

Echinocytes: red blood cells shaped like hedgehogs or sea urchins. The abnormal cell membrane displays an uniform array of relatively small spicules that appear as serrated edges distributed evenly across the entire surface of the cell, as shown in the images of a stained blood film and electron microscopy image. They are associated with disorders leading to intracellular adenosine triphosphate (ATP) depletion. Also called Burr cells.

Ferritin: a blood protein that stores iron inside the body’s cells.

Gallstones:  small stones that form in the gallbladder and bile ducts, which may cause pain

Gene/genetic molecular analysis: tests that look for changes in one or more genes. These types of tests determine the order of DNA building blocks in an individual’s genetic code, a process called DNA sequencing (MedlinePlus).

Gene mutation:  a permanent change in the DNA sequence of a gene, altering the gene’s instructions to make a protein (in this case pyruvate kinase) so that the protein stops working properly

Glycolysis: a multistep process in which glucose (a sugar) is converted into pyruvate and ATP, or energy for cells.

Glucose: is the basic form of all broken down carbohydrates and sugars. It’s an important energy source for living organisms.

Hemoglobin: a protein in red blood cells that transports oxygen around the body

Hemoglobin A1c: a blood test that measures the average blood sugar level over the past 3 months. This test relies on health red cells that last 3 months cannot be used in people with red cell disorders.

Hemoglobinopathy: a group of disorders in which there is abnormal production or structure of the hemoglobin molecule

Hemolytic anemia:  anemia that results from the breakdown of red blood cells faster than they can be made or replaced when they die; low hemoglobin level due to destruction of red blood cells

Hemolysis:  the break down of red blood cells by internal or external factors.

Hyperbilirubinemia: results from elevated total serum bilirubin and unconjugated hyperbilirubinemia and may cause jaundice. In infants, it can have harmful effects on the central nervous system.

Iron chelation therapy: the use of chelating agents to manage or treat iron overload in children and adults.

Iron overload:  an excess of iron in the body

Jaundice: yellowing of the skin

Kernicterus:  damage to the brain and central nervous system in newborn babies caused by high bilirubin levels

Laparoscopic surgery:  minimally invasive (or keyhole) surgery

Liver iron concentration (LIC): an increasingly accurate and noninvasive measurement of iron stores in the liver taken by magnetic resonance imaging (MRI).

Membranopathies: hereditary red blood cell membrane defects resulting in hemolytic anemias such as hereditary spherocytosis, hereditary elliptocytosis, hereditary stomatocytosis, hereditary xerocytosis, and paroxysmal nocturnal hemoglobinuria.

MRI: magnetic resonance imaging scans that use a large magnet and radio waves to look at organs and structures inside the body. MRI may be used to detect iron accumulation in the liver and heart.

Non-spherocytic:  red blood cells are not shaped like the normal doughnut-shape of red blood cells.

Phlebotomy:  withdrawal of blood from the body

PK blood test/PK enzyme activity test/PK deficiency assay test:  The pyruvate kinase test measures the level of the enzyme pyruvate kinase from a patient’s blood sample using a machine called a spectrophotometer.

PKLR gene: expressed in the liver and the red blood cells and provides instructions for producing the enzyme pyruvate kinase.

PKLR gene testing/PKLR genotyping/molecular analysis:  All terms that refer to a molecular test that looks for variations in the DNA of the PKLR gene located on chromosome 1q21 that indicates pyruvate kinase deficiency.

Polychromasia: a condition where the blood smears of patients appear bluish grey indicating an increased number of immature red blood cells called reticulocytes are being released from the bone marrow.

Pulmonary hypertension:  a condition that can occur in people with PK deficiency. High blood pressure affects the arteries of the lungs and the right side of the heart resulting in chest pain and shortness of breath.

Pyruvate:  an important metabolic molecule that is the end product of glycolysis

Pyruvate kinase:  an enzyme that helps break down carbohydrates, via glycolysis, to a form of energy called ATP and pyruvate in cells.

Pyruvate kinase deficiency:  the most common enzyme-related glycolytic defect that results in red cell hemolysis. It is a chronic, hereditary, hemolytic anemia meaning it’s a long-lasting, inherited anemia caused by red blood cells breaking down faster than they can be replaced.

Reticulocytes:  immature red blood cells

Secondary pyruvate kinase deficiency:  pk deficiency that results because of another disease, most commonly, leukemia, and has similar impacts like anemia

Splenectomy:  surgical removal of the spleen

Splenomegaly:  enlargement of the spleen

Unconjugated bilirubin:  unconjugated (indirect) bilirubin must be converted into conjugated (direct) bilirubin in the liver to be excreted from the body.