May 23rd – Sickle-cell (drepanocytosis) anaemia (SCA) is a hereditary blood disorder, characterized by RBCs that assume an abnormal, rigid, sickle shape. Sickle cell anemia is a form of sickle-cell disease in which there is homozygosity for the mutation that causes HbS which deteriorates the cells’ flexibility and results in a risk of various life-threatening complications. Life expectancy is expected to be shortened but improvements and advances in science, patients can live into their 70s or beyond. Individuals with one copy of the defunct gene display both normal and abnormal haemoglobin. This is an example of codominance. Sickle-cell disease occurs more commonly among people whose ancestors lived in tropical and sub-tropical sub-saharan regions where malaria is or was common. Where malaria is common, carrying a single sickle-cell allele (sickle cell trait) confers a selective advantage. Specifically, humans with one of the two alleles of sickle-cell disease show less severe symptoms when infected with malaria. #365DaysOfMicroscopy