A 15-year-old African American female presents to the emergency room with complaints of bilateral thigh and hip pain. The pain has been present for one day and is steadily increasing in severity. Acetaminophen and ibuprofen have not relieved her symptoms. She denies any recent trauma or excessive exercise. She does report feeling fatigued. She reports having similar pain episodes in the past, sometimes requiring hospitalization. On examination she is afebrile (without fever) and in no acute distress. No one in her family has similar episodes. The remainder of her examination is completely normal. Her white blood cell count is elevated at 17,000/mL (nl: 5,000-10,000/mL), and her hemoglobin (Hb) level is decreased at 7.1 g/dL (nl: 12-16 g/dL).
1. What is the most likely diagnosis??
Sickle Cell Anemia
2. What is the molecular genetics behind this disorder??
A single (point) mutation, Glu (hydrophilic) ŕ Val (hydrophobic)
Changing the 20, 30 and 40 structure to produce a “sickle” shape
3. Define the following terms:
Globin: protein part of Hb
Heme: Fe containing prosthetic group, carries O2 to oxygenate tissues
Hemoglobin: Oxygenates tissues
Primary (10) Protein Structure: See Notes
Secondary (20) Protein Structure: See Notes
Tertiary (30) Protein Structure: See Notes
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