sickle-cell anaemia

a type of inherited, haemolytic ANAEMIA (see HAEMOLYSIS ) that is genetically determined and is the most common hereditary disease in the world. It is caused by a RECESSIVE GENE and is manifested when this GENE is inherited from both parents. One AMINO ACID in the HAEMOGLOBIN molecule is substituted, causing the disease, which results in an abnormal type of haemoglobin being precipitated in the red blood cells ( ERYTHROCYTES ) during deprivation of oxygen. This produces the distortion of the cells, which are removed from the circulation, causing anaemia and JAUNDICE . Many people are carriers as a result of inheritance of just one defective gene and because this confers increased resistance to MALARIA , this gene remains at a high level.