<unk>  is a hemoglobin genotype AS and is generally regarded as a benign condition. However, individuals with<unk>  may have rare complications. For example, in November 2010, Dr. Jeffery K. Taubenberger of the National Institutes of Health discovered the earliest proof of sickle-cell disease while looking for the virus of the 1918 flu during the autopsy of an African-American soldier. Taubenberger's autopsy results showed that the soldier suffered a sickle-cell crisis that contributed to his death even though he had only one copy of the gene. There have been calls to reclassify<unk>  as a disease state, based on its malignant clinical presentations. Significance may be greater during exercise. Association with other medical conditions Malaria The<unk>  provides a survival advantage against malaria fatality over people with normal hemoglobin in regions where malaria is endemic. The<unk>  is known to cause significantly fewer deaths due to malaria, especially when Plasmodium falciparum is the causative organism. This is a prime example of natural selection, evidenced by the fact that the geographical distribution of the gene for hemoglobin S and the distribution of malaria in Africa virtually overlap. Because of the unique survival advantage, people with the<unk>  become increasingly numerous as the number of malaria-infected people increases. Conversely, people who have normal hemoglobin tend to succumb to the complications of malaria. The way in which sickle cell protects against malaria is attributed to several different things. One of the more common explanations is that the sickle hemoglobin inhibits the plasmodium parasite from infecting the red blood cells which reduces the number of malaria parasites to infect the host. Another factor is the production of heme oxygenase-1 (HO-1) enzyme, which is highly present in the sickle hemoglobin. This enzyme produces carbon monoxide which has been proven to protect against cerebral malaria. Established associations * Hematuria * Hyposthenuria * Renal medullary carcinoma, a cancer affecting the kidney, is a very rare complication seen in patients with<unk> . * Renal papillary necrosis (only considered "possible" by some sources) * Splenic infarcts at high altitude. Surgery may not always be necessary. * Sudden deaths during physical exertion in African-American US army recruits, and athletes * Urinary<unk>  infection Suggested * Probable: complicated hyphema, venous thromboembolic events, fetal loss, neonatal deaths, and preeclampsia * Possible: acute chest syndrome, asymptomatic bacteriuria, and anemia in pregnancy * Insufficient evidence: retinopathy, cholelithiasis, priapism, leg ulcers, liver necrosis, avascular necrosis of the femoral head, and stroke. An association with complicated migraines has been suggested. There have been reports of pulmonary venous thromboembolism in pregnant women with<unk> , or men during prolonged airflight, and mild strokes and abnormalities on PET scans in children with the<unk> .<unk>  appears to worsen the complications seen in diabetes mellitus type 2 (retinopathy, nephropathy and proteinuria) and provoke hyperosmolar diabetic coma nephropathy, especially in male patients.
Sickle cell trait
Sickle cell disease
Sick cell syndrome
Hereditary spherocytosis
Paroxysmal nocturnal hemoglobinuria
EEM syndrome
Primary hyperoxaluria
Hemoglobinemia