Genomic editing with CRISPR/Cas9 for production of hereditary persistance of fetal haemoglobin Brazilian type as sickle cell disease treatment strategy

Abstract

Sickle cell disease (SCD) is a serious condition, chronic and undoubtedly represents a public health problem in Brazil. The AF is caused by a point mutation in codon 6 of the ² globin gene, leading to a glutamic acid for valine substitution and results in the production of a structurally abnormal hemoglobin, hemoglobin S. Although the cause of the disease has been known for more than fifty years, therapeutic options are still quite limited. The only drug approved for treatment is hydroxyurea and the only curative therapy is bone-marrow transplantation. The transplantation is still limited to major health care centers and for only a few patients who have compatible donors. Thus, it is necessary to develop treatments that can improve the prognosis of the disease. High levels of HbF in the blood are associated with a better clinical outcome in SCD patients. In some individuals, the expression of ³-globin gene persists into adulthood in elevated levels, which is called hereditary persistence of fetal hemoglobin (HPFH). This project is aimed at the use of a substitution of a cytosine (C) by a guanine (G) at position -195 of the globin gene ³A promoter, called non deletional HPFH Brazilian type (nd-HPFH-B), augmenting the levels of HbF. This point mutation is carried out by CRISPR system / Cas9 high fidelity, capable of performing a specific break in the DNA target sequence, thus facilitating homologous recombination of the donor sequence containing the -195 C