Therapy Analysis - Sickle cell anaemia
Breaking the sickle cycle
In 1904, dental student Walter Noel was hospitalized with severe
respiratory distress. Over the next 2 and a half years, Noel was
readmitted several times for muscular rheumatism and bilious attacks.
In routine blood analysis, his physician Dr Ernest Irons discovered
some of his red blood cells (RBCs) to be "peculiarly elongated and
sickle cell shaped". Baffled by this strange observation, Irons and his
attending colleague, Dr. Herrick, consulted with other physicians and
current literature to no avail, with suggestions ranging from hookworm
to malaria. It wasn't until 1922 that the disease was understood and
came to be known as "sickle-cell anaemia".
Sickle-cell anaemia is one of the world's most common genetic disorders and is
believed to have originated from 4 places in Africa and the Indian/Saudi Arabian
subcontinent. It is most common in sub-Saharan Africa, with approximately 25%
of the population carrying the sickle cell trait and 1-2% of all babies born with a
form of the disease. Around 1000 babies in the US are born with sickle cell
disease each year, compared to 45000-90000 babies in Nigeria. It has been
found that the sickle-cell trait is especially prevalent in areas of Africa hard-hit by
malaria. In some regions, as much as 40% of the population carry the trait.
Malaria kills over a million people a year; however, patients with the sickle-cell
trait have been known to show resistance to the mosquito-borne disease. Once
infected by the parasite, blood cells containing abnormal haemoglobin (Hb) tend
to sickle and the infected cells get eliminated by the spleen because of their
shape, along with the parasite. And so in these areas where the sickle-cell gene
is common, immunity against malaria has become a selective advantage.
