CRISPR/Cas9 Beta-globin Gene Targeting: A method to reach a therapeutic target in Sickle cell disease

Introduction: Sickle cell disease (SCD) is one of the most common monogenic disorders worldwide. SCD is caused by an A-to-T point mutation in the sixth codon of the b-globin gene. SCD is associated with substantial morbidity, poor quality of life, and a shortened life expectancy. An alternative to using allogeneic hematopoietic stem cells (HSCs) to cure the b-hemoglobinopathies is to use homologous recombination (HR) to directly modify the HBB gene in the patient’s own HSCs. It circumvents the need for a matched donor and thus avoids the risk of graft versus host disease and graft rejection after HSCT.Method: Two or three bone marrow harvests are required to collect an adequate dose of HSPCs from SCD patients. Recently suggested that plerixafor is potentially a safer mobilizing agent for SCD patients.Results: several months after gene therapy, the total Hb level was almost 12 g/dL, with therapeutic Hb and HbS accounting for 48% and 46% of the Hb tetramers, respectivelyConclusions: The CRISPR/Cas9 complex consists of the Cas9 endonuclease and a 100-nucleotide single guide RNA (sgRNA). Target identification relies first on the identification of a 3-base pair protospacer adjacent motif and then hybridization between a 20-nucleotide stretch of the sgRNA and the DNA target site, which triggers Cas9 to cleave both DNA strands. Genome editing by HR requires the delivery of a DNA donor molecule to serve as a homologous template, which the cellular homologous recombination machinery uses to repair the break by a ‘copy and paste’ method.

کلیدواژه ها:

gene editing ، sickle cell disease ، Transfusion ، CRISPER