Ds is also called Trisomy 21 (Tri = 3). The most common type of Ds is called Nondisjunction, approximately 95 % of people with Down Syndrome have this type and I am pretty sure this is the one Annelies has (we will know for sure once we speak with the Geneticist). Nondisjunction Ds is the failure of one of the reproductive cells (can be the sperm or the egg) to separate during meiosis (this is when the cell divides- normally it would divide into 2 sets of 23 chromosomes. In this case, it divides into one set of 22 (dies off) and one set of 24 chromosomes. When it comes together with the other reproductive cell which carries 23 chromosomes, there is a total of 47 chromosomes instead of 46 (the normal amount). The extra chromosome is an additional 21st chromosome, so instead of 2 21 chromosimes, a person with Ds has 3 of them. Because the 21 chromosome is smaller than the others (it is the smallest one) it carries less genetic material than all the others, and T21/ Ds is survivable as opposed to Trisomy 18 which is much less so.
Approximately 4-5% of people with Ds have "Translocation Trisomey 21". In this case, the extra 21 chromosome attaches itself to anothe chromosome, usually 14, which also results in 3 copies of chromosome #21. As in Nondisjunction T 21, approximately 75 % of cases of Translocation are caused 'spontaneously' during fertilization. 25% of cases of Translocation can be inherited from a parent who has a genetic abnormality, called a 'balanced carrier'. This person has no symptoms and would never know they are a balanced carrier until they have this genetically researched.
A picture of a person's chromosomes is called a "Karyotype", we will have a copy of this for Annelies once we see the Geneticist, and I will post it. Much research is still being done as to specifically which genetic information is located on that 21st chromosome, a lot has been found already and helps in determining what people with Ds should be aware of.
Having this extra chromosome affects individuals in different ways, most significantly health wise. I learned that Ds in itself is the least of your worries. Here is the list of health issues we are grateful we don't have to deal with at the moment:
- Approximately 50% of people with Ds are born with congenital heart defects, many require surgery in the first 6 months of their lives.
- Gastrointestinal problems, partial or total block in the part of the duodenum (just beyond the stomach). Occurance approximately 7 %. Higher occurance of Hirschsprung and Celiac desease. Also possible problems are reflux and constipation, caused by decreased muscle tone. Neither of these are problems for Annelies, and with a healthy diet she should not have constipation issues.
- Decreased muscle tone: Depending on how low the muscle tone is, this affects motor development. Much is done to help with Physical Therapy /Early intervention. Annelies has Low-Normal muscle tone, meaning it is low cpmpared to 'regular' babies, but still in the normal range, and on the high end compated to others with Ds. I am so grateful for this.
- Higher occurances of Umbilical hernia's, Epilepsy.
- One to be aware of is Atlantoaxial Instability: Too much movement between the first and second vertebrea in the neck, 15% occurance rate. This may cause spinal cord damage if not detected and fixed. Annelies will be screened for this around her 3rd B day. If this is a problem, the treatment is surgery. I am hopeful that in the next years, advances will be made for this problem.
- Sight and hearing will have to be screened on a regular basis, probably every 6 months. To me, these are things that can be fixed and I am not afraid of them, but it is so important to catch any possible issues with sight and hearing since they would hamper development.
- Higher occurance of Leukemia
- There are more, but these were the hard hitters for me.
I have been told (and I agree) that this is the best possible time to have a disability. So many advances have been made. Open heart surgeries that were not possible even 15 years ago are now routine.
We plan to live out lives on a day to day basis, without getting too freaked out about what the future holds for Annelies. I see her horizons the same as I see them for Marco, with many opportunities to find out what she enjoys, and build on that. Kids with Ds go to college these days, they play sports, they live on their own, get married, etc. She will have the best of the best of early intervention and therapy to help her on her way, but she will also be expected to live a 'normal' life. When I go back to work, she will attend the same day care Marco goes to, they have already welcomed her with open arms.
There is no reason for me not to be positive and hopeful for our future.