sickle cell disease

 

 I remember having a strong man cry when I was taking his family history: as he related how his son had died as a young adult of sickle cell disease.

Sigh. He didn't recognize me (all white lady doctors look alike) but I recognized him as the uncle of our next door neighbor, who had related the story to me asking about the chance he might pass the gene to his own children..

Racism does exist in medicine, and one example is how sickle cell disease has been ignored by much of medicine and the press. We have fund raisers for Muscular dystrophy but not for sickle cell disease.

And some of the health disparties between black and white population in the US is from this disease.

Sickle cell disease is one of the inherited hemoglobinopathies that are more common in certain ethnic groups (mainly but not only black, and Mediterranean ethnics)

The term sickle cell disease includes different genotypes of homozygous HbS sickle cell anemia (SS) and the double heterozygote states of sickle hemoglobin C disease (SC), sickle beta plus thalassemia (Sβ+Thal), sickle beta zero thalassemia (Sβ0thal), sickle cell anemia with alpha thalassemia (SS αthal), and sickle cell anemia with high fetal hemoglobin (SS+F).2

The treatment was hydration to prevent sickle cell crisis: where low oxygen levels cause the blood cells to change shape to a sickle, and clog the small blood vessels.

Since many end up with a destroyed spleen, we gave them penicillin (and now pneumonia vaccine) and kept an eye out for other bacterial infections like salmonella that can be fatal.

later, it was discovered the hydroxyurea helped prevent sickle cell crisis by raising the percentage of cells with fetal hemoglobin. 

Background: A baby has fetal hemoglobin, which carries oxygen at a lower level than ordinary hemoglobin because the oxygen in utero is lower than you get from breathing on your own, but this gradually disappears after birth. This does not sickle, and if you have enough of this, your blood oxygen stays higher and you are less likely to have a sickle crisis from stress/dehydration etc.

Why does this gene survive when it is fatal? well, because those with one gene for Sickle anemia and one gene for ordinary blood aka "sickle cell trait", are less likely to die of malaria. Thalessemia is another blood disease that has some malaria immunity, but if you get a double gene it can kill you.

In the past sometimes we would transfuse people to give them better percentage of less vulnerable blood cells, but this could lead to iron overload and liver damage.

more recently, stem cell and bone marrow transplant offer a cure, but this is expensive and dangerous and not everyone is able to get this treatment.

and in the past, if you had a woman with sickle cell disease or other similar blood problems, it was considered a medical reason for abortion (although now with modern medicine the risk is smaller).

The possible good news is that using CRISPR, it might be able to actually use one's own cells to replace the abnormal hemoglobin with the fetal hemoglobin gene. CRISPR is a way to cut and paste things into genes.

This more easily readable article on FreeThink explains what is being done, and that the experimental treatment was found to still be working after three years.

(headsup from Instapundit)

CureSickle website has more information on the disease.

cross posted from my regular blog.