Sickle cell trait

Sickle cell trait

Infobox_Disease
Name = Sickle cell trait


Caption =
DiseasesDB =
ICD10 = ICD10|D|57|3|d|55
ICD9 =
ICDO =
OMIM = 603903
MedlinePlus = 000527
eMedicineSubj = search
eMedicineTopic = Sickle%20cell
MeshID =

Sickle cell trait describes the way a person can inherit one of the genes of sickle cell disease, but not develop recurrent symptoms. Sickle cell disease is a blood disorder in which the body produces an abnormal type of the oxygen-carrying substance hemoglobin in the red blood cells. Sickling and sickle cell disease is an adaptive evolutionary response to reduce malaria parasitization of red blood cells.

ickle hemoglobin

Normal hemoglobin is called hemoglobin A, but people with sickle cell disease have only hemoglobin S, which turns normal, round red blood cells into abnormally curved (sickle) shapes.

Normally, a person inherits two genes (one from each parent) that produce beta-globin, a protein needed to produce normal hemoglobin (hemoglobin A). A person with sickle cell trait inherits one normal beta-globin gene (hemoglobin A) and one defective gene (hemoglobin S).

Prevalence

Sickle cell trait prevalence is highest in West Africa (25% of the population). However, it has been described globally in Caucasians in Mediterranean countries of Italy, Greece, and Spain. It has been described Turks, North Africa, Iranians, Arabs, Middle Eastern nations including Iran, and in Indians.Fact|date=September 2008

One out of every ten African-Americans have sickle cell trait.Fact|date=September 2008

Race and Sickle-cell

It is a common misconception that sickle-cell is a "black" disease, meaning that only persons of African ancestry can carry the trait. However, recent studies in race and biomedicine suggest otherwise. The genetic variant which causes sickle hemoglobin can provide increased resistance to malaria if a person only carries one copy of the gene. [http://www.understandingrace.org/humvar/sickle_01.html]

People who come from areas with high prevalence of malaria, such as Africa, the Middle East, southern Europe and South Asia are more likely to carry the sickle-cell trait. It is not connected to skin color or race. [http://www.understandingrace.org/humvar/sickle_02.html]

ymptoms

Sickle cell trait (Hemoglobin genotype AS) is not benign. People with sickle cell trait have symptoms due to co-morbidity and conditions which may cause heat, dehydration, hypoxemia, and sickling. There have been reports of pulmonary venous thromboembolism in pregnant women with sickle cell trait,cite journal |author=Austin H, Key NS, Benson JM, "et al" |title=Sickle cell trait and the risk of venous thromboembolism among blacks |journal=Blood |volume=110 |issue=3 |pages=908–12 |year=2007 |month=August |pmid=17409269 |doi=10.1182/blood-2006-11-057604 |url=] or men during prolonged airflight, mild strokes and abnormalities on PET scans in children with the trait, complicated migraine headaches,cite journal |author=Osuntokun BO, Osuntokun O |title=Complicated migraine and Haemoglobin AS in Nigerians |journal=Br Med J |volume=2 |issue=5814 |pages=621–2 |year=1972 |month=June |pmid=5031686 |doi= |url= |id=PMC|5031686] poor urinary concentrating ability, increased incidence of renal carcinoma, and sudden deaths during physical exertion in US black army recruits,cite journal |author=Kark JA, Posey DM, Schumacher HR, Ruehle CJ |title=Sickle-cell trait as a risk factor for sudden death in physical training |journal=N. Engl. J. Med. |volume=317 |issue=13 |pages=781–7 |year=1987 |month=September |pmid=3627196 |doi= |url=] cite journal |author=Mitchell BL |title=Sickle cell trait and sudden death--bringing it home |journal=J Natl Med Assoc |volume=99 |issue=3 |pages=300–5 |year=2007 |month=March |pmid=17393956 |doi= |url=] splenic infarcts at high altitude, even in white patients with the trait. However, they can pass the sickle cell trait to their children, and in rare cases, exercise-induced dehydration or exhaustion can cause healthy red blood cells to turn sickle-shaped, which can cause death during sporting activities.cite journal |author=Eichner ER |title=Sickle cell trait |journal=J Sport Rehabil |volume=16 |issue=3 |pages=197–203 |year=2007 |month=August |pmid=17923725 |doi= |url=] There have been calls to reclassify sickle cell trait as a disease state, based on its malignant clinical presentations.cite journal |author=Ajayi AA |title=Should the sickle cell trait be reclassified as a disease state? |journal=Eur. J. Intern. Med. |volume=16 |issue=6 |pages=463 |year=2005 |month=October |pmid=16198915 |doi=10.1016/j.ejim.2005.02.010 |url=] Sickle cell trait appears to worsen the complications seen in diabetes mellitus type 2 (retinopathy, nephropathy and proteinuria)cite journal |author=Ajayi AA, Kolawole BA |title=Sickle cell trait and gender influence type 2 diabetic complications in African patients |journal=Eur. J. Intern. Med. |volume=15 |issue=5 |pages=312–315 |year=2004 |month=August |pmid=15450989 |doi=10.1016/j.ejim.2004.06.003 |url=] and provoke hyperosmolar diabetic coma nephropathy) especially in male patients. Athletes with sickle cell trait do not achieve the same level of performance as elite athletes with normal hemoglobin AA. Athletes with sickle cell trait and their instructors must be aware of the dangers of the condition during anaerobic exertion especially in hot and dehydrated conditions.

A person in whom both beta-globin genes are abnormal (they produce hemoglobin S) has sickle cell disease, which can cause serious problems. Both parents must have either the sickle cell trait or the disease itself for a child to have sickle cell disease. Genetic/prenatal counselling is available to reduce the incidence of Hemoglobin SS conceptus.

People who have the sickle cell trait have reduced susceptibility to cerebral malaria, a situation which may be referred to as heterozygote advantage. This is called "balanced polymorphism" where a deleterious gene confers a survival advantage. However, people with the sickle cell trait can still contract severe cases of malaria.

References


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Look at other dictionaries:

  • sickle cell trait — ☆ sickle cell trait n. the heterozygous condition of having one gene for sickle cell hemoglobin and one for normal hemoglobin: ordinarily this does not cause anemia or sicklemia …   English World dictionary

  • sickle-cell trait — n a usu. asymptomatic blood condition in which some red blood cells tend to sickle but usu. not enough to produce anemia and which occurs in individuals (as those of African or Mediterranean descent) who are heterozygous for the gene controlling… …   Medical dictionary

  • sickle-cell trait — sickle cell trait. См. признак серповидных клеток. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Sickle cell trait — The condition in which a person has one copy of the gene for sickle cell (and is called a sickle heterozygote) but does not have sickle cell disease (which requires two copies of the sickle cell gene). If two people with sickle cell trait mate… …   Medical dictionary

  • sickle-cell trait — noun : an inherited blood condition in which some red blood cells tend to sickle but usually not enough to produce anemia, which occurs primarily in individuals of Negro ancestry, and which is held to result from heterozygosity for a semidominant …   Useful english dictionary

  • sickle cell trait — sick′le cell trait n. pat the usu. asymptomatic hereditary condition that occurs when a person inherits from only one parent the abnormal hemoglobin gene characteristic of sickle cell anemia • Etymology: 1925–30 …   From formal English to slang

  • sickle cell trait — Pathol. the usually asymptomatic hereditary condition that occurs when a person inherits from only one parent the abnormal hemoglobin gene characteristic of sickle cell anemia. Also called sicklemia. [1925 30] * * * …   Universalium

  • sickle cell trait — Pathol. the usually asymptomatic hereditary condition that occurs when a person inherits from only one parent the abnormal hemoglobin gene characteristic of sickle cell anemia. Also called sicklemia. [1925 30] …   Useful english dictionary

  • sickle-cell trait — noun Date: 1928 an inherited usually asymptomatic blood condition in which some red blood cells tend to sickle but usually not enough to produce anemia and that occurs primarily in individuals of African, Mediterranean, or southwest Asian… …   New Collegiate Dictionary

  • sickle cell — n 1) an abnormal red blood cell of crescent shape 2) a condition characterized by sickle cells: SICKLE CELL ANEMIA, SICKLE CELL TRAIT * * * see drepanocyte * * * an erythrocyte shaped like a sickle or crescent owing to the presence of …   Medical dictionary

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