In a good news for the persons suffering with blood disorders like sickle cell anemia and thalassemia, a team of researchers has, for the first time successfully edited genes of the patients of severe red blood congenital disease with CRISPR-Cas9 technology.

The advantage of this approach is that it uses the patient’s cells or say, DNA of the patient’s blood cell is  modified. There is no need of a donor. The study is published in the New England Journal of Medicine.

For layman understanding, it can be called as gene correction therapy to actually completely correct the affected DNA sequence. Presently, blood transfusion and bone marrow transplant are conventional modes of treatment but having their own constraints.

However, development of CRISPR-Cas9 technology is expected to revolutionize the world of genetic disorders which are passed down from parent to child. Many die without getting adequate treatment while many suffer in pain throughout their life.

Researchers cured two patients of separate cases of severe red blood congenital diseases--sickle cell anemia and Thalassemia --by safely modifying DNA of the patients’ blood cells.

In the paper ‘CRISPR-Cas9 Gene Editing for Sickle Cell Disease and beta-Thalassemia’, Dr Damiano Rondelli, the Michael Reese Professor of Hematology at the University of Illinois Chicago said gene editing modified the DNA of stem cells by deleting the gene BCL11A, the gene responsible for suppressing foetal haemoglobin production.

By doing so, stem cells start producing foetal haemoglobin so that patients with congenital haemoglobin defects (beta thalassemia or sickle cell disease) make enough foetal haemoglobin to overcome the effect of the defective haemoglobin that causes their disease. The results are encouraging, said the study.

The advantage of this approach is that it uses the patient’s cells with no need for a donor. Also, the gene manipulation does not use a viral vector as with other gene therapy studies but is done with electroporation (quick production of pores into the cells with high voltage) which is known to have low risk of off-target gene activation.

Dr Nita Radhakrishnan, HOD, Department of Paediatric Haematology-Oncology, Super Specialty Paediatric Hospital and PG Teaching Institute (SSPHPGT), Noida  hoped that the treatment can be a game-changer for world health.

For, she said, sickle cell disease and beta thalassemia and other congenital blood disorders are major diseases in the world. The present modes of treatments have their limitations.

Blood transfusion often leads to iron overload and organ damage while bone marrow transplant is a costly, risky and invasive treatment available only to patients who can find suitable donors with matching blood stem cells. Also, limited bone marrow transplantation facilities and expertise within the country mean that most patients cannot access this treatment, Dr Radhakrishnan added.

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