A sickle disease patient could be given a new lease of life after scientists modified her DNA in an experimental procedure.
Victoria Gray, 34, has suffered from the red blood cell defect from a young age and regularly endures pangs of searing pain that ‘make a grown woman scream’.
Many people with the condition do not live past 40. The mother-of-four from Forest, Mississippi, fears she will miss her children growing up.
But she has been given fresh hope after taking part in a clinical trial where doctors edited her genes using a cutting-edge method called CRISPR.
The experiment has been hailed a ‘phenomenal’ step forward’ by medicine experts in the scientific community.
Like all sickle cell disease patients, Ms Gray’s red blood cells have morphed from round discs to sticky crescents which clog up the blood stream and deplete organs’ supply of oxygen.
Sickle cell disease patients have crescent-shaped red blood cells which clog up blood streams and cause searing pain. But a team based at the TriStar Centennial Medical Center in Nashville, Tennessee have used CRISPR gene-editing to treat this condition
Figures suggest around 100,000 people in the US and 15,000 in the UK suffer from the genetic malformation.
Stem cells can cure patients of the condition – but come with risks including X, Y and Z.
If the treatment given to Ms Gray is proven to work, it could ‘potentially change the lives of many patients’, according to doctors.
Dr Haydar Frangoul and colleagues based at the TriStar Centennial Medical Center in Nashville, Tennessee, carried out the procedure on Ms Gray.
The treatment works by editing her cells to start producing foetal haemoglobin, a protein not usually found in humans over six months old.
But Dr Frangoul and his team hope that it will prevent red blood cells from becoming misshapen and clogging up the blood stream.
Several months ago, Dr Frangoul and his team extracted billions of bone marrow cells from Ms Gray before editing them using CRISPR.
This DNA cut-and-paste tool, known formally as CRISPR-Cas9, implants, removes or alters genetic code into cells to change its characteristic and functions.
The components of CRISPR-Cas9 – the DNA sequence and the enzymes needed to implant it – are sent into the body on the back of a harmless virus so scientists can control where they go.
How scientists used CRISPR editing to treat sickle cell disease
To treat Victoria Gray’s sickle disease, scientists used a cutting-edge gene-editing tool called CRISPR-Cas9.
In this method, scientists create DNA code which attaches to a gene.
The enzyme Cas9 is then used to cut the gene. This triggers the gene’s self-healing process, which absorbs the new code and changes the cell function.
In Ms Gray’s case, it involved extracting billions of the patients bone marrow cells and implanting new genetic code to change their function.
The scientists engineered these new cells so that they would produce foetal haemoglobin, a protein normally present in humans under six months old.
This haemoglobin, the team hopes, will prevent the red blood cells from being misshapen and clogging up the blood stream.
The newly coded cells were then infused back into the body.
Cas9 enzymes can then cut strands of DNA, effectively turning off a gene, or remove sections of DNA to be replaced with the CRISPRs, which are new sections sent in to change the gene and have an effect they have been pre-programmed to produce.
After editing Ms Gray’s cells to produce foetal haemoglobin, the Nashville scientists returned them to her body.
Although it is too early to judge whether the treatment has worked, Dr Frangoul is optimistic.
‘This is a big moment for Victoria and for this pivotal trial. Because if we can show that this therapy is safe and effective, it can potentially change the lives of many patients,’ he told National Public Radio.
‘We are very hopeful that this will work for Victoria, but we don’t know that yet.’
Ms Gray, who was forced to drop out of school and is frequently bed-bound, is longing for the treatment to work so she can spend time with her children without worrying about pain sudden crippling pain.
She said: ‘This would be mind-blowing. I can’t imagine the lives that could be saved if this thing actually works.
‘Yeah, oh my God. Just to not have to deal with that pain anymore is enough.’
The trial was sponsored by Vertex Pharmaceuticals and CRISPR Therapeutics as part of a wider programme which will see 45 patients treated across the US, Canada and Europe.
Dr James Davies, of the Radcliffe Department of Medicine at Oxford University, hailed the advances being made by the Nashville team.
He told MailOnline: ‘It’s a phenomenal step. This is the first time people have used gene editing in this way, which would have been inconceivable 10 years ago.
‘This offers hope of a cure and is a huge step forward.’
He likened the feat of the scientists of taking a book with three billion characters and pinpointing a single word before changing it.
Dr Davies also said that CRISPR gene-editing is much less risky than than a blood transplant from someone else, during which five per cent of patients die.
Since CRISPR editing emerged, clinical trials involving DNA editing has ballooned.
Another government-approved study in the pipeline will see scientists modify genes in people’s retina cells to improve their vision.
WHAT IS SICKLE CELL DISEASE?
Sickle cell disease is the umbrella term for a group of inherited conditions that severely affect red blood cells.
Around 15,000 people in the UK are sufferers and it is particularly common in people of African or Caribbean descent.
Healthy red blood cells – produced by stem cells within bone marrow – are biconcaved discs that can bend and flex easily.
However, in those with sickle cell disease, faulty stem cells produce red blood cells that are crescent shaped.
They are rigid, unable to squeeze through smaller blood vessels and prone to causing blockages that deprive parts of the body of oxygen.
Sufferers are not expected to live beyond 60 and treatment mainly focuses on alleviating symptoms, such as pain and infections, through blood transfusions and painkillers.