Overview
The first assignment in GMS 6604 is the creation of a report that comprises detailed responses to the eight questions that can be found at the end of the textbook chapter on Sickle Cell Anemia (Chapter 2). The SCA chapter contains eight (8) questions that focus on the disease. Some of the information required to provide detailed responses to these questions can be found in the chapter, but all will require additional research using resources available on the internet, such as “PubMed” or other sites and texts that feature more extensive information on SCA.
Assignment 1: Sickle Cell Anemia
1. Patients who have hemoglobin SS as well as a mutation that produces hereditary persistence of fetal hemoglobin have few symptoms of sickle cell disease. Explain why this is the case. 2. An infant has 96% hemoglobin F and 4% hemoglobin S at birth. What are the possible diagnoses? What tests can be done to confirm the newborn screening test? 3. Couples who each have sickle cell trait have three children; none of their children have sickle cell disease. They tell you they do not want to have another child be cause they know there is a one in four possibility for their children to have sickle cell disease, and they already have three unaffected children. What is the probability their next child will have sickle cell disease? If they have another child and this child has sickle cell disease, then what is the probability that one of the other children will be an HLA match? 4. Describe the concept of allostery as it applies to hemoglobin and to regulatory enzymes. 5. A mother complains to you at a clinic visit that her 10-year-old child, homozygous for hemoglobin S, still has enuresis at night. Can you explain to her, and to yourself, why this might be the case? What other organ dysfunction might be expected in a child this young? 6. Why does deoxygenated hemoglobin S polymerize? Besides polymerization, what are the causes of the clinical manifestations of sickle cell disease? 7. How could the child in the case study have died from pneumococcal sepsis if this bacterium was sensitive to penicillin? 8. If both hemoglobin A and hemoglobin S have the same oxygen-carrying capacity and exhibit the same oxygen saturation curves when at low hemoglobin concentrations, then why does hemoglobin S have a decreased oxygen-carrying capacity at the concentrations found in the red cell? Trace the path of a red cell in sickle cell disease from the lungs to the capillary bed and back to the lungs, noting the hemoglobin changes that are likely to occur during the journey