Sickle-Cell Disease & What Might Have Cured Them

Dr. Barry H. Kaplan’s response to the NY Times article titled “These Patients Had Sickle-Cell Disease. Experimental Therapies Might Have Cured Them.” Written by: Gina Kolata

Nothing shows the astounding progress we are making in medicine more than a January 26th article in The New York Times. Sickle cell anemia is a dreadful disease. It is caused by an inherited mistake in one of the genes that make hemoglobin. A double dose of that mistake results in the disease. I have cared for many of these patients for decades. Their life expectancy is 44 years and they can suffer from repeated episodes of pain, strokes, kidney failure and other serious complications. We have made some progress but thousands of patients in this country and tens of thousands around the world continue to suffer.

There are now three approaches that show enormous promise to cure this disease. The first of these is something called CRISPR, a new technique that allows scientists to edit genes almost like a spell checker. The bad gene is removed and a good gene replaces it. It is not simple but the technology has been applied to a few patients and appears to be successful. The second technique is to use a safe virus to carry the good gene into bone marrow stem cells.

The third and what I think is the most promising involves allowing fetal hemoglobin to persist. In utero and for 6 months after birth humans make something called fetal hemoglobin, There is a switch built into our genes which turns off fetal hemoglobin and allows adult hemoglobin to take over. A new technique blocks the switch so more fetal hemoglobin is made instead of the hemoglobin with the sickle gene mistake. Even a relatively small amount of fetal hemoglobin will block the problems associated with sickle hemoglobin and cure the disease. Fetal hemoglobin can function in oxygen transport just like adult hemoglobin.

All three of these approaches are in testing and a small number of patients have already been successfully treated. The estimate is that one of these treatments will be available within three years. Just think we may be able to cure sickle cell anemia!

I have been a physician for nearly 57 years and a hematologist since 1957. I have never been so thrilled with what has been accomplished in the past few years

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