Sickle Cell Disease: Genetic
Guest: Dr. Sherron Jackson – Pediatrics - Hematology/Oncology
Host: Dr. Linda Austin – Psychiatry
Linda Austin: I’m Dr. Linda Austin. I’m talking, today, with Dr. Sherron Jackson
who is Associate Professor of Hematology/Oncology at the Children’s Hospital
here at the Medical University of South Carolina. Dr. Jackson, you have been an expert for many
years in a very serious and significant illness, sickle cell anemia. When you explain to parents for the first
time just what this illness is that they may bring a child in with, how do you
explain it to them? What is it?
Sherron Jackson: I generally explain
that this is a congenital disorder. Most
of the families that I meet nowadays are new parents whose infant has been
diagnosed from newborn screening. I
explain that this is a condition affecting the red blood cells of the body, the
parts of the body that are responsible for carrying oxygen to all the
tissues. And I explain that the
hemoglobin in these red blood cells is different, and because of that genetic
difference, the babies and children are susceptible to changes in the red blood
cells, the sickling, they call it. That
describes the shape of the cell. Instead
of it being a round donut-like shape, the blood cells actually take on a
crescent moon shape that makes it difficult for those blood cells to travel
through the blood stream.
Linda Austin: Now, when the cells have
that difficulty in traveling, why does that create problems for the child?
Sherron Jackson: The problem is in the
very small blood vessels. The diameter
is just enough to carry one blood cell, one round blood cell. So, when there are a number of the sickle, or
crescent, cells clumped together, they do not flow through the blood stream as
they normally would. And this renders
injury to the tissues, injury to the blood vessels, and it ultimately results
in pain in those parts of the body. Many
in our community have heard of sickle cell disease and have associated sickle
cell with some kind of painful symptoms and painful episodes.
Linda Austin: Now, you say “in our
community” because this is most commonly an illness of African-Americans?
Sherron Jackson: That’s exactly
right. Predominantly, African-Americans
will carry the sickle gene, sickle trait,
we say, and have the tendency to pass that gene on to their children. When a couple has a child, if each parent has
trait, there’s a 25 percent chance that the gene gets passed to the
children. The condition doesn’t just
affect African-Americans. But, in our
country, it’s predominantly those of African heritage. But we find sickle disease in other ethnic
groups, particularly those who are from the Middle East and the Mediterranean
countries, as well as South America.
Linda Austin: Now, when a parent has a
child with sickle cell anemia, does this come as a shock to them, that they may
have no idea that they actually are carriers of the trait until their child is
Sherron Jackson: Exactly.
Linda Austin: Or will they often have
cousins with sickle cell anemia?
Sherron Jackson: Well, because of our
high incidence of sickle trait in the low country, there are many families who
know of someone in their family that has sickle trait or sickle disease. So, I think persons in our community are a
bit more aware because they do have family members with sickle disease or sickle
trait. But I’m often surprised at the
number of new families that I meet where the parents have a baby with sickle
disease, but neither parent is aware that they have sickle cell trait
themselves. So, it’s a shock to them
that their new healthy baby has been diagnosed with a chronic condition.
Linda Austin: So then, if a person has,
let’s say an aunt, uncle, cousin or a grandparent who had sickle cell anemia,
would you recommend that they have genetic testing before they get pregnant,
just so that they are not taken by surprise?
How would you counsel a person?
Sherron Jackson: Absolutely. We would recommend any adults in our
community, women and men, especially African-American women and men, but
anyone, really, should have the opportunity to do screening for sickle cell
trait so that we can identify persons who may have children with sickle cell
disease. There are opportunities for
adults to be screened at no charge in our community. And, if you’re ever attending a health fair,
there will often be a booth set up for sickle cell trait testing that our DHEC,
our state health agency, sponsors. This
is one way that we can identify adults who have sickle cell trait in the
community, before they have children.
Linda Austin: So, if somebody is
listening to this podcast and is interested in getting screened, at no charge,
is there a number they can call? Who
should they contact?
Sherron Jackson: The COBRA Foundation is
our local sickle cell agency. This is a
community organization that will provide the screening, sickle cell trait
screening, free of charge.
Linda Austin: Dr. Jackson, do you know
the telephone number to call for someone who would like screening for sickle
Sherron Jackson: Yes. The phone number for COBRA is (843) 225-4866.
Austin: Thank you. So then, let’s imagine that a young woman is
thinking of getting pregnant. She gets
screened. In fact, she has sickle cell
trait. What would be the next step for
her to take, to evaluate her real risk?
Sherron Jackson: Once we know that an
individual has sickle cell trait, and especially women of childbearing age, but
women and men, we would recommend that they have counseling through the COBRA
Foundation. It would be an opportunity to
give them information about the risks and the chances that their child would
have sickle cell disease if their partner has sickle cell trait.
sometimes confusing because the persons with trait are completely healthy and
do not have symptoms of pain or anemia, which we associate with sickle cell
disease. And sometimes individuals will
be concerned that there’s something wrong if they’re diagnosed with trait. But, really, the main emphasis is on
educating a person, if they have trait, to make them aware of their potential
for having a child with sickle cell disease.
But there would not be any symptoms or episodes of illness in a person
who has sickle cell trait.
Linda Austin: And if, let’s say, a woman
or a man has sickle cell trait, which means they’re a carrier but not affected,
and they marry someone who does not have trait, they could produce a child who
might have trait, or might not have trait, but they would not produce a child
who has sickle cell anemia, is that correct?
Sherron Jackson: That’s correct. It would take two parents, each parent having
sickle trait, having a sickle gene, having a child together. And, again, even for that couple, every
pregnancy carries a 25 percent chance, so there is the possibility for the
couple to have a baby with sickle cell disease.
The baby could have sickle trait, or the baby might inherit each
parent’s healthy, normal, genes and not have sickle disease or trait. But, we want families to understand that
there is the 25 percent risk of having a baby with sickle disease if each parent
has sickle cell trait.
Linda Austin: What percentage of
African-Americans in the low country carry the sickle cell trait?
Sherron Jackson: We have a higher
incidence of trait in the low country than other parts of the United States. Sometimes we believe it’s as high as 10
percent, or even 12 percent, in our community, so we have the expectation that
we may have more children born to couples, living in the low country, that have
Linda Austin: So, if I were to quickly
do the math on that, let’s say a woman has trait, she would have a 10 percent
[chance] of finding a man who might have trait, and then they would have a 1 in
4 chance of having a baby with sickle cell anemia. So, her chances would be 1 in 40 if he were
untested, correct? Is that right?
Sherron Jackson: That’s right.
Linda Austin: Okay.
Sherron Jackson: And, often, the males
in the community are less likely to be screened. Most of the women of childbearing age are
screened at a pregnancy visit during the early trimester, first trimester, of
pregnancy. And, of course, at that
point, we really would like to know if the partner, the husband, has been
screened, and we need to know if that individual has sickle trait. But, it’s very difficult sometimes to get the
partner to come in to be tested.
Ideally, this would be information that would help that couple make a
decision or at least be aware, when the baby is born, the baby will be tested. The baby may have sickle disease if each of
those parents has sickle cell trait.
Linda Austin: Dr. Jackson, we’ve really
covered some of the genetic issues.
Let’s pause there and do another podcast on what, really, is the course
of the illness in a baby who is born with sickle cell anemia. Thank you so much.
Sherron Jackson: Thank you.
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