16 February 2015
A team of scientists at the Royal Hallamshire Hospital have identified four previously undiscovered variants of haemoglobin, the protein in red blood cells which transports oxygen around the body and gives blood its red colour.
One of the new variants has been approved for entry into a global database, with the others expected to follow. Identifying haemoglobin variants can help to diagnose blood disorders.
The new variants were discovered by the haemoglobinopathy diagnostics department at Sheffield Teaching Hospitals, which launched its Haemoglobin Mass Spectrometry service in 2013. The service is led by Consultant Haematologist Dr Josh Wright. It is the only Trust in the region, and one of only a few in the UK and Europe, to use tandem mass spectrometry to analyse haemoglobin. The technique can identify abnormalities by measuring the mass of the amino acid chains that make up haemoglobin.
Although most variants are not clinically significant, some can affect the ability of haemoglobin to carry oxygen, or the stability of the haemoglobin molecule. Some haemoglobin abnormalities can cause serious blood disorders such as sickle cell anaemia if the faulty gene is passed on by both parents.
All pregnant women in Sheffield are screened by the service as part of the National Sickle Cell and Thalassaemia Screening Programme. It aims to ensure access to diagnostic tests in a timely manner, so that the Trust’s counsellors can provide information and support to prospective parents.
“Haemoglobin transports oxygen from the lungs around the body, so anything that interferes with its ability to do that, or that decreases the lifespan of the red cells, can be significant,” said Biomedical Scientist Jason Eyre, who leads the service along with Dr Wright.
“If we find a variant in screening that we don’t recognise, then we don’t know if it is significant. So it is important to be able to correctly identify haemoglobin variants. Once a clinician knows the root cause of a condition, it can then be managed. Building up the database helps us to improve that knowledge base.”
Haemoglobin mass spectrometry works by using enzymes to chop up the chain of amino acids in haemoglobin and measuring the mass of each of the constituent parts to identify where the abnormality is. It is considerably cheaper than the traditional method of DNA analysis.
Using this technique, the Trust team is able to identify about 95% of the 1,200 known haemoglobin variants. When a previously unknown variant is found, it is submitted for approval for entry into the global Database of Human Haemoglobin Variants and Thalassemias.
The newly identified haemoglobin variant already approved for entry onto the database has been named Hb Brigante, after the Celtic tribe that was native to Yorkshire prior to the Roman invasion. The other three variants are in the process of being submitted.
This specialist service is expanding and is increasingly taking on work from other Trusts.
Dr Wright said: “We are delighted to be able to offer this service to other areas of the country and hope in time to develop this technique further and diagnose other diseases of the red blood cell.”
ENDS
Picture caption: Consultant Haematologist Dr Josh Wright (left) and Biomedical Scientist Jason Eyre.
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