FAQ - Down's Syndrome

  1. How is Mosaicism diagnosed?
  2. Is it possible to predict a child?s IQ based on the number of normal cells present in the study?
  3. How does it effect her development?
  4. How does mosaic Down Syndrome happen?
  5. My baby has mosaic Down Syndrome. What does that mean?
  6. Is iron dangerous for children with DS? Is craniosacral therapy (cranial therapy) useful for children with Down Syndrome?
  7. What is the life expectancy for people with Down Syndrome?
  8. Are atropine eye drops dangerous for children with DS?
  9. I have read on the internet about treating DS with a type of Indian medicine called Ayurvedic therapy. Is there any evidence that this can help children with DS?
  10. How likely is a person to have a child with Down Syndrome if he/she has a sibling with DS?
  11. If maternal age over 35 years is a risk factor for having babies with DS, why are more than half of all babies with DS born to women under 35 years?
  12. Does fluoride intake increase the risk of having a child with DS?
  13. Is fluoride safe to give to children with Down Syndrome?
  14. Are adults with Down Syndrome sterile?
  15. Does the use of drugs or alcohol in a parent before or during pregnancy cause children to have Down Syndrome?
  16. Is Down Syndrome inherited?
  17. Are there medical treatments for Down Syndrome?
  18. Can Down Syndrome be cured or outgrown?
  19. How prevalent is Alzheimer Disease (pre-senile dementia) in adults with Down Syndrome?
  20. Are people with Down Syndrome at high risk of developing Alzheimer's Disease later in life?
  21. Do people with Down Syndrome have normal life expectancies?
  22. Are children with Down Syndrome born only to older mothers?
  23. What tests are used for prenatal diagnosis? When is prenatal diagnosis recommended?
  24. Can people with Down Syndrome have babies?
  25. What are a couple's chances of having a child with Down Syndrome?
  26. What is the incidence of Down Syndrome?

Down's Syndrome

Q: How is Mosaicism diagnosed?
A:

The usual way in which mosaic Down Syndrome is discovered is through genetic testing of the baby's blood. Typically, 20 to 25 cells are examined. If some of the cells have trisomy 21 and some don't, then the diagnosis of mosaicism is made. However, this blood test can only determine the level of mosaicism in the blood cell line. While mosaicism can occur in just one cell line (some blood cells have trisomy 21 and the rest don't), it can also occur across cell lines (skin cells may have trisomy 21 while other cell lines don't). In the latter case, it may be more difficult to diagnose mosaicism. When mosaicism is suspected but not confirmed through the blood test, other cell types may be tested: skin and bone marrow are most commonly the next cells checked. Because skin cells and brain cells arise from the same type of cell at the beginning of fetal development (ectoderm), many doctors believe that skin cell tests reflect the chromosomal makeup of the brain cells as well.

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Q: Is it possible to predict a child?s IQ based on the number of normal cells present in the study?
A:

In most cases chromosome studies are done using white blood cells. The number of blood cells containing 46 chromosomes may not accurately reflect the number of skin cells, heart cells, or brain cells with 46 chromosomes. Therefore, it is impossible to predict what affect, if any, the presence of these chromosomally normal cells will have on a child?s development. The parents of children with mosaic Down Syndrome are like the parents of any other child. Your child?s strengths and weaknesses will only be revealed over time.

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Q: How does it effect her development?
A:

Every child is born with a unique set of talents and abilities. However, it is impossible to predict what these talents and abilities will be. This is true for a child who inherits 46 chromosomes. This is true for a child with trisomy 21 (Down Syndrome), and this is true for a child with mosaic Down Syndrome. While it is impossible to tell you what the future holds for your daughter, I can share with you information about other children with mosaic Down Syndrome.

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Q: How does mosaic Down Syndrome happen?
A:

Ordinarily, when an egg and a sperm are joined at conception, a single cell is created with a total of 46 chromosomes. These chromosomes are copied, the copies are separated, and the cell then divides to create two identical ?daughter? cells. The chromosomes in these two cells are copied, the copies divide and four cells are created. These four cells become eight cells. Eight cells become 16 cells, and so on. If nothing disrupts the chromosome replication and separation process, each cell in the body should have the same number of chromosomes that were present in the fertilized egg.

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Q: My baby has mosaic Down Syndrome. What does that mean?
A:

Children with mosaic Down Syndrome have two distinct cell groupings. In some cells there is a total of 46 chromosomes, which is the ?typical? group. In other cells there is an extra copy of the chromosome #21, making 47 cells total for this group.

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Q: Is iron dangerous for children with DS? Is craniosacral therapy (cranial therapy) useful for children with Down Syndrome?
A:

Proponents of cranial therapy claim that skull bones can be manipulated to relieve many disorders. To quote the website of the Craniosacral Therapy Assoc. of the UK: "Dr William Sutherland, an American osteopath, discovered intrinsic movements of the bones of the skull around the turn of the century. His further research revealed different rhythmic tidal motions in the body. These movements, which can be measured with delicate scientific instruments, are a direct expression of the health of the system.

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Q: What is the life expectancy for people with Down Syndrome?
A:

This is a more complicated question than it seems, because how you answer it depends on how you look at the statistics. First, looking at how long adults with DS live: the last major published article to look at this was in California in 1991, and the results in that study may not be the same for any other place in the world. But that study looked at over 12,000 people with DS and found that major medical problems were not a consistent predictor of mortality, which was a common belief. Instead, self-help skills were the best predictor of life expectancy.

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Q: Are atropine eye drops dangerous for children with DS?
A:

No. Atropine eye drops are used to dilate the pupil during eye exams, and also to treat the conditions amblyopia, esotropia and strabismus. Children with DS seem to have a greater dilation in response to atropine, and the dilation appears to last longer as well. However, there is no evidence that atropine eye drops has any effect on the body beyond the eyes. (North RV, Ophthal Physiol Opt, 7(2): 109-114, 1987)

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Q: I have read on the internet about treating DS with a type of Indian medicine called Ayurvedic therapy. Is there any evidence that this can help children with DS?
A:

Not at the present time. To quote Drs. Lodha and Bragga of the Dept of Pediatrics, All India Institute of Medical Sciences in New Delhi: "Evidence-based studies on the efficacy and safety of traditional Indian medicines are limited. The essential ingredient in most formulations is not precisely defined. High quality studies are necessary to evaluate and compare the value of traditional Indian drugs to modern medicine." (Ann Acad Med Singapore 29(1):37-41, 2000)

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Q: How likely is a person to have a child with Down Syndrome if he/she has a sibling with DS?
A:

For the vast majority of people, having a sibling with DS does not increase one's risk of having a child with DS. That's because 95% of all cases of DS are not inherited. The chromosomal test on the person with DS will show how likely it is to be an inherited case.

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Q: If maternal age over 35 years is a risk factor for having babies with DS, why are more than half of all babies with DS born to women under 35 years?
A:

While it is much more common for babies with DS to be born to women over 35 years of age (see my risk page), women under 35 have a higher birth rate. No risk factors have been found yet for women under 35 years of age, but several research groups are looking at this question.

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Q: Does fluoride intake increase the risk of having a child with DS?
A:

No. A study in 1980 of births in 44 US cities proved conclusively that there was no difference in the rate of births of children with DS in cities with and without fluoridated water supply (Erickson JD, Teratology 21:177-80,1980).

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Q: Is fluoride safe to give to children with Down Syndrome?
A:

There is no evidence that fluoride, used correctly, is harmful to children with DS than any other child. Fluoride in the proper amounts is not toxic.

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Q: Are adults with Down Syndrome sterile?
A:

Women with DS are fertile. Men with DS have traditionally been considered sterile; however, there have been two documented cases of adult men with DS fathering children.

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Q: Does the use of drugs or alcohol in a parent before or during pregnancy cause children to have Down Syndrome?
A:

No. Down Syndrome occurs at conception. So nothing in the pregnancy can cause Down Syndrome to occur. As for prior to conception, the research all shows that drug or alcohol use does not increase the risk of having a child with DS.

 

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Q: Is Down Syndrome inherited?
A:

Only 3 to 5% of cases are inherited; the rest arise as an accident of chromosome arrangement during meiosis. For details, see my essay on the origin of trisomy 21 or Dr. Paul Benke's essay on the types of DS, and the risk and recurrence risk of DS.

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Q: Are there medical treatments for Down Syndrome?
A:

Although there have been proposed medical treatments for Down Syndrome, none of them have been proven effective. These treatments have included thyroid hormone, pituitary extract, glutamic acid, dimthyl sulfoxide, Sicca cell therapy, five-hydroxytryptophan, various vitamin and mineral therapies and lately, nootropic drugs such as piracetam. Sicca cell therapy has been shown by several reports to be dangerous. Careful studies looking at the use of vitamin supplementation showed no benefit.

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Q: Can Down Syndrome be cured or outgrown?
A:

No. Just as we cannot change your genetic make-up, we cannot change the genetic make-up of a person with Down Syndrome. The effects of Down Syndrome, however, can be modified by providing good medical care, good education and good parental support.

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Q: How prevalent is Alzheimer Disease (pre-senile dementia) in adults with Down Syndrome?
A:

In the 1960's, autopsies of adults with DS showed that after about age 30 years, they all have the characteristic plaques and neurofibrillary tangles associated with Alzheimer disease. From that finding, it was assumed that all adults with DS would eventually get Alzheimer dementia if they lived long enough. However, population studies in the 1980s and '90s showed that the percentage of adults with DS who actually get dementia range from 16% to 50%, depending on the criteria used to diagnose dementia.

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Q: Are people with Down Syndrome at high risk of developing Alzheimer's Disease later in life?
A:

Possibly, although the final answer on this is not available. Although it is true that some of the Alzheimer-like changes in the physical brain occur in most, if not all, people with Down Syndrome as they age, the clinical appearance of dementia does not always occur. The latest thinking is that because of premature aging, Alzheimer's dementia that does develop comes on at an earlier age but that the incidence of dementia may or may not be increased. It would be wrong to assume that an adult with Down Syndrome who appears to have developed dementia does in fact have Alzheimer's dementia.

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Q: Do people with Down Syndrome have normal life expectancies?
A:

No. Generally, life expectancy is reduced by 10-20 years. Some people with Down Syndrome, however, have been known to live into their 80's.

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Q: Are children with Down Syndrome born only to older mothers?
A:

No. Although the risk of Down Syndrome increases with age, a child with Down Syndrome can be born to a mother at any age. Although only 5-8% of pregnancies occur in women over the age of 35, they account for 20% of Down Syndrome births. Therefore, 80% of children with Down Syndrome are born to women who are less than 35 years of age.

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Q: What tests are used for prenatal diagnosis? When is prenatal diagnosis recommended?
A:

Until recently, the answer was to offer amniocentesis to all pregnant women age 35 or older and to those women who had a previous child with Down Syndrome. Now some doctors reccommend screening tests for all pregnancies.

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Q: Can people with Down Syndrome have babies?
A:

The chance of a woman with Down Syndrome having a baby with Down Syndrome is theoretically 50%. There is one documented instance of fertility in a male with Down Syndrome; the mother also had Down Syndrome. The pregnancy miscarried about half-way through.

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Q: What are a couple's chances of having a child with Down Syndrome?
A:

In the usual circumstance, the chances depend upon the age of the mother. The odds of having a child with Down Syndrome at age 35 are approximately 1 in 350. Under age 25, the odds are about 1 in 1400 and at age 40 the odds are about 1 in 100. (Thompson, et al., 1991) The chances of a parent of a child with Trisomy 21 having another child with Down Syndrome is approximately 1 in 100. If the child has a translocation, the recurrence risk can be as high as 100% or as low as 2%.

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Q: What is the incidence of Down Syndrome?
A:

The incidence of Down Syndrome has been variously reported as 1 in 800 live births to 1 in 1,100 live births. A recent estimate in the United States puts the incidence at about 1 in 1,000. There is no association between Down Syndrome and any given culture, ethnic group, socioeconomic status or geographic region. (CDC, 1994) (Thompson, McInnes, & Willard, 1991)

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