Sickle Haemoglobin and Varients

Substitution of the amino acid glutamic acid by valine at position 6 of the beta globin gene (HBB glu6val) results in a mutant haemoglobin that polymerizes at low oxygen pressure. This mutation results in sickle shaped cells under hypoxic conditions. The haemoglobin gets its name, sickle haemoglobin, from the phenomena. Sickling is responsible for symptoms of sickle cell anaemia. Shown above are sickle cells from the smear of a patient with sickle cell anaemia.
HbS is an autosomal co-dominant trait. Homozygous individuals suffer from sickle cell anaemia (SS). The clinical profile of compound heterozygous depends on the non-HbS allele.

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Sickle Haemoglobin and Varients 

Source:All About Blood
Image credits: All About Blood

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