CDKL5 Genetics 101

As I start most of my posts... "before Sonya's diagnosis" ...I had no knowledge of genetics.  Since we learned of Sonya's CDKL5 diagnosis, we have met with a couple of amazing geneticists, so now I have a semi understanding of what occurred on her gene.  I realized that some of you might want to know yourselves, so I will attempt to share my knowledge.  After our recent visit to the Rett Clinic (they see CDKL5 patients 6 times a year since CDKL5 is considered Atypical Rett) in Denver, Colorado last week, I have gained even more information regarding Sonya's specific mutation.

Sonya has her own specific mutation.  There are rare instances where more than one child could have the same mutations, however, the way Sonya's mutated, it would be nearly impossible for anther CDKL5 gene to present in the same manner.

Like nearly all children with a CDKL5 mutation, Sonya's is de novo.  This is just a fancy way of saying the mutation was not passed down from either Sam or me.  It happened around the time of conception, randomly.  Why? We don't know.  It was not caused by anything I did or did not do.

Now to get down to the nitty gritty.

The CDKL5's main purpose is to ensure healthy brain cell function and communication with other brain cells. The CDKL5 protein is considered to be a large, efficient protein and is found all over the brain. Therefore any type of mutation to the CDKL5 gene is considered disastrous, as the protein being produced may for all intents and purposes be considered junk and not usable. 

If you think about a gene like a series of box cars lined up on a railroad track that is where I will begin.  Each box car carries information that is vital to the complete function of the train.  Many things can happen with the box cars that negatively impact the train.  For example, box cars could be removed from the track, there could be box cars added to the track or there could be box cars that are switched while on the track.  When any one of these things occurs, it has devastating results.

Let's talk about Sonya.  In Sonya's case, she had two box cars that were removed from the track.  Coming from a long line of over achievers, Sonya "realized" there was a mistake and tried to fix it by adding in an additional car to replace the two cars that had fallen off the track (that was unnecessary Sonzee, but we appreciate your efforts).  After this box car was added in, the remaining cars moved down the track.   

All genes have a predetermined "stop code".  When a series of numbers come together and repeat three times it signals to the gene that the shop is closed.  Unfortunately, when Sonya's replacement box car was added, it caused the remaining cars to be shifted down.  So shortly after Sonya's box car addition, the combination of the cars in the order they were placed on the railroad track created one of those stop codes.  This in turn ended the production of the CDKL5 gene and made whatever parts of the gene that were created essentially unable to perform their duties.

If you want more scientific terms, Sonya has a deletion and insertion in her CDKL5 gene that created a frameshift mutation which prematurely stopped the code of her CDKL5 gene.

What does this mean for the Sonzee?  Well, we are still unsure what the future holds for our little bear, but we do know that she will be able to learn new things, it will just take her 10000 times of performing the same skills over and over again for the skill to be learned.  She will have severe delays; however, with constant hard work, strength, and determination, she will be one amazing Sonzee bear!  Our biggest challenge, will be keeping her seizures "under control" so she can continue to move in an upward trajectory gaining skills.

Sonzee with Mr. Mike last week at PT

I have so much information to share from our visit to the Rett Clinic so stay tuned!