Sickle- cell disease(SCD),or sickle-cell anaemia(SCA) or drepanocytosis,is hereditary blood disorder,characterized by blood cells that has an abnormal,rigid,sickle shape.Sickling decreases cells’ flexibility, results of various complications.
Sickling occurs because mutation in the haemoglobin gene.Individuals with copies of defunct gene display normal,abnormal haemoglobin.example of codominance.
Life expectancy is shortened .In 1994,the U.S,average life expectancy with this condition was estimated ,42 years males,and 48 years in females.Thanks to greater management patients live far beyond 70s.
Sickle -cell disease is more commonly among people who have ancestors lived tropical,subtropical,sub-sharan regions where malaria is or was common,carries a single sickle -cell gene(sickle-cell trait),humans with one or two alleles of sickle-cell disease have less severe symptoms when infected with malaria.
Sickle - cell anaemia is a form of sickle-cell disease in where homozygosity for mutation causes Hbs.referred to as Hbss,SS disease haemoglobin S permutations of these names.Hereozygous people,that have only one sickle gene and one normal adult haemoglobin gene,condition referred to HbAs or sickle cell trait.
Signs and symptoms
Sickle-cell disease lead to a lot of other acute and chronic complications, several does have a high mortality rate.
The term sickle cell crisis or sickling crisis is used to describe several conditions that occur in patients with the sickle cell disease,results in anemia and crises.Many types includes:Vaso-occlusive crisis,aplastic crisis,sequestration crisis,haemolytic crisis among others.Most sickle cell episodes crises last five to seven days.Infection, dehydration,acidosis(favor sickling)which can trigger.In most cases no predisposing cause has been identified.