The Link Between Down Syndrome and Leukemia

Kathryn E. Vinson, MS, CCRC

When anyone becomes ill, it is a natural reaction to look for someone, or something, to blame. But when it is the most innocent among us – our children – that need seems to grow exponentially.  As a parent we look at ourselves and wonder if it was something that we did.  Was it a GMO food?  Was it antibiotics?  Was it a vaccine?  For many parents, the answer will never be clear – we may guess, but we may never really know.

Every so often, we do get an answer.  Researchers at the Dana Farber Cancer Institute have uncovered a genetic link between acute lymphoblastic leukemia and children with Down Syndrome.  Let’s take some time today to talk about Down Syndrome, ALL, and the potential for this research.

Down Syndrome

Down Syndrome is the result of a person having an extra copy of the 21st chromosome. We each normally have 46 chromosomes – 23 from each of our biological parents.  There are actually several ways that Downs can occur, but the most widely known is due to advanced maternal age.  You see, when our mothers are pregnant with us, we ladies have already produced every egg that we will ever make.  But here’s the catch – the process that makes these eggs, meiosis, is frozen, and doesn’t complete until we ovulate that egg.  As menopause doesn’t occur until our late 40s or 50s (for most of us), these ova are in a state of suspended animation for up to half a century. Sometimes, when the chromosomes separate, they don’t separate correctly and an egg can wind up with two copies of a chromosome, or an extra portion of a chromosome. When that egg joins with a sperm, you have a baby with an extra chromosome.

With some chromosomes, this is fatal, and results in a miscarriage.  With others, it is not fatal, but can cause major medical problems down the road.  This is the case with Trisomy 21, or Down Syndrome.  Most of us are aware that these lovely children often have heart, respiratory, and thyroid conditions. But we don’t often know about the increased risk of cancer unless that child is close to us.  Sadly, children born with Down Syndrome stand a 20 times increased risk of B cell ALL over other similarly matched children.

What’s the link?

While this connection between Downs and ALL has been known for almost a century, the “Why” hasn’t been so clear.  Andrew Lane, MD, PhD, of the Dana Farber Cancer Institute, along with numerous colleagues, set out to understand just that.  By studying mice with an extra copy of 31 genes found on the 21st chromosome, they were able to identify a protein that was suppressed – PRC2.  What they found was that this protein suppression allowed B-cells, cells that typically fight disease, to grow uncontrollably in an immature state.

When the research team compared this gene sequence to children with Down Syndrome and ALL, they found that the PRC2 gene sequence was silenced in some way.  When this PRC2 gene is not present, or not functioning properly, it allows the B-cells to grown and replicate while not yet mature.

That mechanism became clear when they discovered a specific gene – HMGN1.  The extra copy of the HMGN1 gene in people with Down Syndrome plays a major role in turning off PRC2, allowing those B-cells to grow in an out of control manner.

What this means for cancer research

Over the last several years, researchers in all parts of world have identified cancers that may result from problems with the PCR1 and PCR2 gene sequences.  It appears that both overexpression of the gene and suppression of the gene have been implicated in numerous cancers including, but not limited to: breast, prostate, gastric, lung, liver, leukemias, ovarian, and lymphomas.

By identifying these connections, we have the ability to understand where we may be at increased risk.  Researchers also have a target for treatments should a cancer’s genotype suggest these genetic markers.

If a young person in your life has been affected by cancer of any type, take a look at our listing of Gifts for Kids with cancer.  There are some amazing products there to help them through their treatments, to help brighten their beautiful spirits, and to just help them feel like kids.

As always, much love, many prayers, and abundant blessings to all of the warriors out there!


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