What is the etiology of sickle cell anemia?

A 17-year-old African American female from the inner city complains of severe chest and abdominal pain. Upon examination, the attending physician performs an EKG, chest x-ray, and an abdominal and chest clinical examination and finds nothing. Assuming she is drug seeking, he sends her home. She comes back to the ER 4 hours later and now you see the patient. She explains that she was running track this past afternoon at school and that despite being very hot (100 F) she pushed on. Afterwards, she starts feeling extensive pain in her chest and abdomen. She has jaundiced eyes, her blood pressure is 98/50, pulse is 112, T = 99.9 F, R = 28. The pain seems out of proportion to the physical findings. During a review of her medical history, she tells the provider that she has history of sickle cell anemia. At this time, it is determined that she is in a sickle cell crisis.
What is the etiology of sickle cell anemia?
Describe in detail the pathophysiological process of sickle cell anemia.
Identify hallmark signs identified from the physical exam and symptoms.
Describe the pathophysiology of complications of sickle cell anemia.
What teaching related to her diagnosis would you provide?
In addition to the textbook( McCance, K. L., Huether, S. E., Brashers, V. L., & Rote, N. S. (2013). Pathophysiology: The biologic basis for disease in adults and children (7th ed.). St. Louis, MO: Mosby). utilize at least one peer-reviewed, evidence based resource to develop your post.