Posted by & filed under Rare Disease, Vibrant Gene.

(Part 1)

 Surprised baby
Photo by Erin Lee

 

The UK is the first country in the world to legalize the use of 3-parent IVF techniques.  The FDA is currently reviewing the technique for use in the US.  How can three parents create one biological baby?  Much of this post may sound stranger than fiction…

 

For Starters, What is IVF?

In its simplest terms, IVF (or in vitro fertilization) is the creation of human embryos in a lab, by mixing eggs and sperm.   Embryos are then implanted into the mother-to-be’s womb.  Until this point, IVF was limited to folks who experience fertility issues, or need to use donor egg or sperm as commonly seen in same-sex couples.  But this week marked an epic breakthrough in IVF technology use.

 

Mitochondria: not your average organelle

Mitochondria are organelles (think ‘mini organs’) found inside each of the trillion cells in your body:  blood cells, skin cells, heart cells etc.  (Picture a chicken egg, the yolk is the nucleus and houses your DNA; the egg white is where all the organelles hang out.)  Mitochondria act as  powerhouses by taking in molecules and breaking them down to a usable source of energy for your cells.  The body of a person with mitochondrial disease is starved for energy, especially their brain and heart because these organs require a large amount of energy to function.

 

I personally know folks with mitochondrial disease.  Many have symptoms similar to chronic depression, or chronic fatigue, amongst a litany of other symptoms.  Some face risks of kidney or heart failure during their lifetime.  Striving to prevent possible mitochondrial disease in future generations is a worthwhile endeavor.

 

What Makes Mitochondria Amazing?

Mitochondria have their own genome.  It is tiny, the genome only contributes 37 genes (compared to around 25,000 found in our nuclear genome).  And the organization of these genes is very strange.  They overlap with one another, and together form a large ring….much like bacterial genomes.  There is no coincidence there.  Mitochondria were once sovereign beings.  Early in human history, our cells engulfed bacteria, having them play the role of power generators.  The relationship was symbiotic-we gave them food, they gave us energy, and eventually the bacteria took up permanent residence.  They retain genetic material, which we continue to use mostly for energy production.

How do you inherit mitochondrial genes?

Unlike our 25,000 genes found in our nuclear DNA (which we inherit half from mom, half from dad) 100.0% of mitochondria and their accompanying genes came from the mother.  Her egg at the time of conception was saturated with mitochondria.  Dad’s sperm swam by using a single mitochondria to power the tail (or flagellum), and proceeded to inject its nuclear DNA.  The sperm’s single mitochondria was left outside the newly fertilized egg.

If a mother carries a mutation in one of her mitochondrial genes, every pregnancy carries a high risk of mitochondrial disease.  The 3-parent IVF technology, now legal in the UK, is a game changer. It allows such families to have children free of such disease.

 

How does the IVF lab work its magic?

Here’s the brilliant work-around.  The mother with the mitochondrial disease gene contributes her egg, the father provides his sperm, and a third woman donates a healthy egg.  The lab carefully removes the nuclear DNA from the second egg, leaving the healthy mitochondria intact.  The lab then injects the nuclear DNA from the mother.  A single sperm is injected into the new, healthy egg, and the embryo is implanted into the mother’s womb.  This kiddo then will have the nuclear DNA from one mother, nuclear DNA from the father, and mitochondrial DNA from a third parent.

 

From a scientific standpoint, this marks a historic breakthrough in reproductive technology.  And for the thousands of families suffering with mitochondrial disorders, this is very exciting news.  For the first time, mothers with mitochondrial diseases can have healthy biological children of their own.

 

But there are some social implications we might need to consider, and we will tackle these in part 2.

 

 

 

Posted by & filed under Direct-to-Consumer DNA Testing, Vibrant Gene.

One Christmas, I thought it would be fun to try out at-home DNA testing for my then-fiance and for myself.  I recall sitting side by side on our overstuffed couch, spitting into plastic test tubes and laughing at the slobbery mess we were making.

After about a month of waiting, the results were in.  We again plopped ourselves down on the couch with our laptop and logged in to glimpse what was in our stars.

My fiance’s testing was rather uninteresting (not that we were complaining) but we learned that some of his Bulgarian ancestors were Italian.

When it came to be my turn, my heart started racing.  I thought, “Wow, does this happen to all of my patients?  Do they feel weak in the knees at this moment?”  As my luck would have it, I had inherited one gene with one working copy and one non-working copy.

I’m a carrier of GJB2?!  (Technically, I have a variant that renders one copy of this gene non-working).

I sat, stunned, staring at the screen.

I knew what the implications were.  I knew that while I myself would never have deafness due to this mutation, my future kids could.  If my fiance was also a carrier.  According to his test result, he is not a carrier but this testing was from 23andMe, and the lab’s clinical reporting has since been shut down by the FDA for many issues.  Can we trust he’s not a carrier?  How accurate were these results?  Who could I turn to for follow up testing?

I first contacted my PCP who was overly taxed with acute cases, and made it clear following up with genetic testing not a top priority.  I wasn’t yet pregnant and anyway wasn’t genetics [my] specialty?  My OB/Gyn was willing to meet with me, but he didn’t feel comfortable running the test himself.  I kept shaking my head, thinking, “Why is access to basic genetics care so difficult?”  Eventually I found an obstetrician that would run a multi-gene panel that included GJB2.  My obstetrician was really lovely, but she felt uncomfortable interpreting the test result, and left me to figure out follow up care.  Should we have my now-husband tested?  What would we do with the results?  Should we inform our family members, or keep it private?  We sat down together and talked for a long while, having to make some big decisions on our own.  It left me wondering what a patient without my professional training would have done.

The lesson I learned from being a genetics patient was that persistence pays.  Genetics is a specialized field and there are few trained professionals available to help.  Sometimes takes a little extra time and plenty of determination to find the right provider.

My aim is to have Vibrant Gene provide access to genetics care for all-comers.  Without knowing my carrier status, I may have been facing a horror story of having children with debilitating conditions–diseases you wouldn’t wish on your worst enemy.  It’s time folks are able to utilize the latest genetic technology to its fullest potential.

With a Vibrant Gene consultation, you will feel knowledgeable, empowered and able to make smart decisions about your genetic health.

We look forward to speaking with you!