Sickle Cell Anemia

Gene fuels age-related obesity and diabetes

Practically everyone gets fatter as they get older, but some people can blame their genes for the extra padding. Researchers have shown that two different mutations in a gene called ankyrin-B cause cells to suck up glucose ...

Jul 13, 2015
popularity183 comments 1

Sickle cell anemia as malaria defense

Sickle cell anemia causes pain, fatigue and delayed growth, all because of a lack of enough healthy red blood cells. And yet genetic mutations that cause it - recessive genes for the oxygen-carrying hemoglobin protein - have ...

Nov 30, 2011
popularity0 comments 0

Sickle-cell disease (SCD), or sickle-cell anaemia (or anemia, SCA) or drepanocytosis, is an autosomal recessive genetic blood disorder with overdominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various complications. The sickling occurs because of a mutation in the hemoglobin gene. Life expectancy is shortened. In 1994, in the US, the average life expectancy of persons with this condition was estimated to be 42 years in males and 48 years in females, but today, thanks to better management of the disease, patients can live into their 50s or beyond. In the UK, the current life expectancy is estimated to be 53–60 years of age.

Sickle-cell disease, usually presenting in childhood, occurs more commonly in people (or their descendants) from parts of tropical and sub-tropical regions where malaria is or was common. One-third of all indigenous inhabitants of Sub-Saharan Africa carry the gene, because in areas where malaria is common, there is a fitness benefit in carrying only a single sickle-cell gene (sickle cell trait). Those with only one of the two alleles of the sickle-cell disease, while not totally resistant, are more tolerant to the infection and thus show less severe symptoms when infected.

The prevalence of the disease in the United States is approximately 1 in 5,000, mostly affecting Americans of Sub-Saharan African descent, according to the National Institutes of Health. In the United States, about 1 out of 500 African-American children born will have sickle-cell anaemia.

Sickle-cell anaemia is the name of a specific form of sickle-cell disease in which there is homozygosity for the mutation that causes HbS. Sickle-cell anaemia is also referred to as "HbSS", "SS disease", "haemoglobin S" or permutations thereof. In heterozygous people, who have only one sickle gene and one normal adult haemoglobin gene, it is referred to as "HbAS" or "sickle cell trait". Other, rarer forms of sickle-cell disease include sickle-haemoglobin C disease (HbSC), sickle beta-plus-thalassaemia (HbS/β+) and sickle beta-zero-thalassaemia (HbS/β0). These other forms of sickle-cell disease are compound heterozygous states in which the person has only one copy of the mutation that causes HbS and one copy of another abnormal haemoglobin allele.

The term disease is applied, because the inherited abnormality causes a pathological condition that can lead to death and severe complications. Not all inherited variants of haemoglobin are detrimental, a concept known as genetic polymorphism.

This text uses material from Wikipedia licensed under CC BY-SA

Latest Spotlight News

Damaged nerve cells communicate with stem cells

Nerve cells damaged in diseases such as multiple sclerosis (MS), 'talk' to stem cells in the same way that they communicate with other nerve cells, calling out for 'first aid', according to new research from the University ...

Repeating aloud to another person boosts recall

Repeating aloud boosts verbal memory, especially when you do it while addressing another person, says Professor Victor Boucher of the University of Montreal's Department of Linguistics and Translation. His findings are the ...

How the brain's wiring leads to cognitive control

How does the brain determine which direction to let its thoughts fly? Looking for the mechanisms behind cognitive control of thought, researchers at the University of Pennsylvania, University of California and United States ...

Runner's high linked to cannabinoid receptors in mice

(Medical Xpress)—A team of researchers from several institutions in Germany has found a link between cannabinoid receptors in mice and what is commonly known as "runner's high." In their paper published in Proceedings of ...