Gene Editing: Evidence of Success Against Sickle Cell

It’s nice to have news that is authentic and extremely positive. Science delivers again.

Sickle cell anemia is a genetic disease that disproportionately affects black Americans. A new treatment involving gene-editing technology offers the prospect of a cure.

What is sickle cell? Its a defect in the hemoglobin protein that affects the shape of red blood cells that carry oxygen to organs in the body. The defect in shape can cause these cells to dam up, causing debilitating pain, organ damage, increased risk of infection, swelling of hands and feet, vision issues, and eventually premature death. See graphic below.

Source: Wikipedia

The average life expectancy of a patient with sickle cell is no more than 60 years. Treatment can include infection prevention with vaccination and antibiotics, high fluid intake, folic acid supplementation, and pain medication. Other measures may include blood transfusion and the medication hydroxycarbamide (hydroxyurea). A small percentage of people can be cured by a transplant of bone marrow cells.(1)

In an experimental treatment on a patient, Victoria Gray, some of her hempglobin was removed and edited using the CRISPR technology, converting it into non-sickle fetal hemoglobin.(3) Fetal hemoglobin is produced by fetuses to acquire oxygen from the mother’s body. Production of fetal hemoglobin stops after birth. Eleven months after that treatment, 46% of her hemoglobin is of this fetal variety, more than 97% of her red blood cells contain some of this fetal protein, and virtually all of her sickle cell symptoms are gone.(6) That means no blood transfusions, no ER visits and no hospitalizations as she had previously needed.

There have been patients in Europe undergoing this treatment for genetic diseases similar to sickle cell (thalassemia) with similar results.

Some version of this therapy may be possible with other genetic diseases.

This treatment was developed by Vertex Pharmaceuticals and CRISPR Thearaputics, both of Boston, Massachusetts, and administered by the Sarah Cannon Research Institute in Nashville, Tennessee.

Sources:

  1. https://en.wikipedia.org/wiki/Sickle_cell_disease
  2. https://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/symptoms-causes/syc-20355876
  3. https://www.livescience.com/58790-crispr-explained.html
  4. http://www.crisprtx.com/#programs
  5. https://www.advancedsciencenews.com/the-first-crispr-gene-therapy-to-cure-sickle-cell-disease/
  6. https://www.npr.org/sections/health-shots/2020/06/23/877543610/a-year-in-1st-patient-to-get-gene-editing-for-sickle-cell-disease-is-thriving

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