I had a few people: Orcinus [Crazy Elephant King] (#31718) and Phantom StarsX ^ↀᴥↀ^ (#92256) tell me that this would be better in mutations.
Thank you Phantom for Pointing out that this can be a mutation within a person's body (people being born with Anemia).

"Sickle-cell anemia. People with sickle-cell anemia have a gene that causes the blood protein hemoglobin to form abnormally. As a result, red blood cells are produced in a sickle shape. “This can cause painful episodes called crises, and even strokes and heart attacks,” Murray says. People with sickle-cell anemia may also experience swelling in the hands and feet and a reduced ability to fight infection. Sickle-cell anemia is most common in African-Americans, Murray says, but it also sometimes affects people of Hispanic, Indian, and Mediterranean descent." - Jennifer Acosta Scott



How it looks in the blood stream:


(thanks to Husk for this picture and much more information.)

This essentially means that when these blood cells form a sickle shape they can die early and leave a very low amount of healthy red blood cells and are unable to carry enough oxygen throughout the body. Hemoglobin S cells can only live 16 days, compared to regular red blood cells that can last up to 120 days before being replaces by new cells.

Some questions maybe asked on:

a. What would this look like on our lions?
b. How would it affect our lions?
c. What causes it to happen?

Art Style Idea:


(Sorry, I have really bad art. qq)

[NEW] There would also be swelling in the joints of the lion, plus other infections.


a. The answer to that is simple! Some of the noticeable signs on a human for anemia fatigue, pain, infections and delayed development. So if they were to do art for Anemia on a lion it would be probably that they are sitting, or laying down from being extremely tired because of the lack of blood/iron, maybe overtime develop infections or scars. (Essentially art on lion would look like they are exhausted)

b. Anemia affects our lions on the way of maybe not being able to hunt, not a lot of energy, and unable to do normal tasks of other lions/lionesses. (I think they'd still be able to hunt but not as many times in a day if they have Anemia)

c.



"People with sickle cell disease have a kind of hemoglobin called hemoglobin S, or HbS. HbS molecules tend to clump together. This makes red blood cells sticky, stiff, and more fragile. HbS also causes cells to form into a curved, sickle shape." - Kidshealth.org

"People with two copies of the sickle cell gene have the disease. People who carry only one copy of the sickle cell gene do not have the disease, but may pass the gene on to their children." - "Understanding Evolution" (two lions would carry the gene but not have the disease, making them able to pass it onto their cub and them having Sickle Cell Anemia)

"Symptoms usually begin after a few months of age. (Before that age, the baby has a different hemoglobin, called fetal hemoglobin, which is not affected by the sickle cell gene.)" - Patient.info

Lions can die between ages of 9-13

I am currently unsure of how to maybe treat the Anemia other than maybe having like bone marrow from other animals being eaten by the lion/lioness.

Ideas from Comments: Lionesses dying with miscarriages if they have sickle cell. Higher chance for miscarriages.
Male lions with sickle cell are unable to be king.
Smaller bodies due to not enough oxygen.
Sickle Cell males die faster than females.




Weird Fact: Sickle Cell Anemia was a genetic mutation that happened thousands of years ago in malaria-prone regions in Africa. People with Sickle Cell Anemia are unable to get malaria.


Please ask questions and post suggestions because this isn't really everything I want to put on here yet! I want opinion from the community on making this happen!

[MORE GOING TO BE ADDED FOR INFORMATION]

Sources:
http://www.everydayhealth.com/anemia/anemia-and-heredity.aspx
http://evolution.berkeley.edu/evolibrary/article/0_0_0/mutations_06
http://kidshealth.org/EN/images/illustrations/sickleCell-400x214-rd1-enIL.jpg
http://kidshealth.org/en/teens/sickle-cell-anemia.html
http://patient.info/health/sickle-cell-disease-and-sickle-cell-anaemia-leaflet
American Academy of Orthopaedic Surgeons