When your child is diagnosed with an unbalanced chromosomal translocation the first thing you ask is, “What IS that??” Then you realize you probably should have paid closer attention in high school biology…
An unbalanced chromosomal translocation between 3p25.3 and 9p21.3. This derivative chromosome shows a deletion of 3p26.3-3p25.3 (approximately 9.1 MB…which is apparently huge) and a duplication of 9p24.3-9p21.3 (23.2 MB in size).
I know. It’s a mouthful.
Chromosome 9 is uncharted in comparison to Chromosome 3, so the focus of Avery’s disorder and treatment revolves around what we know about “3p- Syndrome.” The severity of the condition and the signs and symptoms depend on the exact size and location of the deletion and which genes are involved. Common symptoms shared by many people (but not all) with this deletion include: poor growth, developmental delay, intellectual disability, distinctive facial features, autism spectrum disorder, an unusually small head (microcephaly), and poor muscle tone (hypotonia). Most known cases, including Avery’s, are not inherited—there was a random glitch somewhere along the line (maybe I stood too close to the microwave at some point? Sigh. We’ll never know.), but people with this disorder can pass the deletion on to their children. source
Read more about 3p- Syndrome here
Q: What is an unbalanced translocation?
A: When the 23 pairs of chromosomes were lining up to divide they misaligned slightly causing a small section on the end of one of the two chromosome # 3s to break off. Where it went, nobody knows. At the same time, a larger section of one of the two #9 chromosomes made a copy of itself, which then attached itself to the end of the damaged #3. Crazy right? In short, there are genes missing from chromosome 3 and genes duplicated from chromosome 9. In theory, this should have devastating results. In reality, Avery has GREATLY surpassed everybody’s expectations. Our geneticist thinks the duplicated genes may be compensating somehow for the missing genetic material. In any case, this girl is a rock star.
Q: What is this syndrome called?
A: A syndrome is named when a number of people present with the same missing or duplicated chromosomal material. Since Avery is the only known person so far with this particular genetic combination, no “official” name is given. We’re going with Super Girl Syndrome. 🙂
Q: Why did this happen?
A: This is a completely random (de novo) occurrence. Avery’s dad and I were tested and we are not carriers. This defect in either the sperm or egg, occurred spontaneously, long before conception for reasons unknown.
Q: What affects have been observed so far?
A: Avery has global developmental delays — gross and fine motor delays, expressive and receptive language disorder and significant learning delays) mild hypotonia, clinodactyly, attention and memory issues, extremely high tolerance for pain, Epilepsy, Mitral Valve Prolapse and a heart murmur.
Q: What does the future hold in terms of health and learning/mental delays?
A: Avery has 62 genes duplicated on chromosome 9. This is a huge chunk, genetically speaking. Little is known about this area (not as much as many of the other chromosomes), but we do know two of these genes are linked to two forms of blood cancers. This is something to monitor by blood test every few years. So far, all is clear.
Learning/mental Delays: Avery has 16 genes missing. Three of these have been linked as the cause of mental delays, specifically related to memory. In early childhood, children learn many things by remembering and repeating. Avery may have trouble remembering and recalling things, therefore it takes her a longer to “learn” since she has to understand a concept fully before she can repeat it and extend upon it. Avery will need to learn in a different way or find ways around this disability.
Ataxia 15: Avery is missing the one gene responsible for this dominant disorder. There are actually 18 types of this disease. This is a disease where slowly over time, people have trouble walking and balancing. SCA15 is one of the milder and slower progressing forms. It only affects the cerebellum, not the spinal cord (some of the other forms affect both). This means that though this disorder is probable (but not definite!), it will not be as severe.
Muscular Dystrophy: Avery is missing one of the dominant genes (CAV3) linked a form of MD called Limb Girdle Muscular Dystrophy. There are several other genes involved that she DOES have intact, so there is a good chance that another gene could compensate for the missing protein and this might never become an issue.
Cardiac Issues: Mutations identified in the CAV3 gene can also lead to Hyperkalemia or rippling muscle disease. Other mutations in Caveolin causes Long QT Syndrome-9. Avery is tested for this disorder on a yearly basis and precautions are taken in terms of medications prescribed in order to limit the chance of promoting an arrhythmia.
Genes are one thing. Jeans are another…
If I could wear jeans every day, I would. But not actual “mom jeans”. You know the kind — unflattering, high waisted, UGLY. To avoid causing your children embarrassment, mid-to-low rise jeans that better suit your mum bum are required and rear pockets are strongly advised.
If your blue jeans:
- are older than dirt
- covered in dirt
- make your rear look square or droopy or flat
- result in “hungry bum” (you know what I’m talking ’bout)
- or cause teenagers to snicker and point as you walk by…
….you might be wearing Mom Jeans. If you are, please, please stop.