Kunj sickness track - Page 3

Sickle-cell disease (SCD), also known as sickle-cell anaemia (SCA), is a group of genetically passed down blood disorders.^[1] It results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells. This leads to a rigid, sickle-like shape under certain circumstances.^[1] Problems in sickle cell disease typically begin around 5 to 6 months of age. A number of health problems may develop, such as attacks of pain ("sickle-cell crisis"), anemia, bacterial infections, and stroke.^[2] Long term pain may develop as people get older. The average life expectancy in the developed world is 50 years.^[1]

Sickle-cell disease occurs when a person inherits two abnormal copies of the haemoglobin gene, one from each parent.^[3] Several subtypes exist, depending on the exact mutation in each haemoglobin gene.^[1] An attack can be set off by temperature changes, stress, dehydration, and high altitude.^[2] A person with a single abnormal copy does not usually have symptoms and is said to havesickle-cell trait.^[3] Such people are also referred to as carriers.^[4] Diagnosis is by a blood test and some countries test all babies at birth for the disease.^[5] Testing is also possible during pregnancy.^[5]

The complications of sickle-cell disease can be managed to a large extent with vaccination, preventive antibiotics, high fluid intake,folic acid supplementation, and pain medication.^[4][6] Other measures may include blood transfusion, and the medicationhydroxycarbamide (hydroxyurea).^[6] A small proportion of people can be cured by a transplant of bone marrow cells.^[1]

As of 2013 about 3.2 million people have sickle-cell disease while an additional 43 million have sickle-cell trait.^[7] About 80% of sickle-cell disease cases are believed to occur in sub-Saharan Africa.^[8] It also occurs relatively frequently in parts of India, the Arabian peninsula, and among people of African origin living in other parts of the world.^[9] In 2013, it resulted in 176,000 deaths, up from 113,000 deaths in 1990.^[10] The condition was first described in the medical literature by the American physician James B. Herrick in 1910.^[11][12] In 1949 the genetic transmission was determined by E. A. Beet and J. V. Neel. In 1954 the protective effect againstmalaria of sickle-cell trait was determined.^[12]