Other types of Sickle Cell Disease

Sickle Cell Anaemia is the most common type of Sickle Cell Disease but there are a couple of other disorders associated with cell sickling.

All types of Sickle Cell Disease are characterised by always having an S allele in the haemoglobin beta chain, this causes the production of Haemoglobin S.

The other allele differs in these other disorders, but as mentioned in the Genetics section the other allele in Sickle Cell Anaemia is another S allele. 

Haemoglobin SC disease

This is a disorder where one allele codes for Haemoglobin S and one allele codes for Haemoglobin C. This disorder shows many of the same symptoms as Sickle Cell Anaemia but is predominantly a weaker phenotype though it can manifest as an equal severity.

The phenotype is more severe than homozygous C disease.

Sickle/beta-thalassemia  

In this condition in addition to the S allele, a beta-thalassemia allele is also present. This allele produces normal Haemoglobin but in reduced amounts. The severity of this condition depends of the amount of normal Haemoglobin produced from beta-thalassemia. This disorder is common is Mediterranean areas.

Sickle Cell trait is also classified as a type of Sickle Cell disease but it has been mentioned thoroughly in the Genetics section.