Feb 21, 2005
by Len Leshin, MD, FAAP
|Copyright 2000, 2002, 2005 All rights reserved
|Note: This page covers questions I frequently get by e-mail about Down syndrome ("DS") and that don't fit into my other essays. This page will be added to over time.|
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.
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.
|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.
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.
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)
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.
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.
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)
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. (The rate of Alzhemier disease in the general population is 5 to 10%.) The diagnosis of Alzheimer-type dementia in adults with cognitive disorders is very difficult, and has been complicated by the fact that many medical conditions seen in adults with DS may mimic cognitive deterioration. So the true prevalence of Alzheimer's dementia in DS may not yet be known.
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)
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. Adults with DS and good self-help skills (mobility, self-feeding) could be expected to live into their 50s, while those with poor self-help skills were expected to live into their 40s. (Eyman RK, Amer J Mental Retard, 95(6): 603-612,1991) However, it would be foolish to predict how long a baby born now with DS would live as so many things can change for them medically and socially in the next decades.
Looking at this question from a slightly different view, we can ask what is the survival rate for infants born with DS. A study from Europe in 1997 found that in babies born with DS, 88% were alive at 1 year and 82% alive at 10 years. The major cause of death in the first year of life was due to heart defects and/or their complications. If you split the group into with and without congenital heart disease, 80% of babies with heart defects were alive after one year, and 96% of babies with DS with no heart defects were alive after one year. Again, these statistics may change for other parts of the world. (Hayes C et al, Int J Epid, 26(4): 822-829, 1997)
Q: 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. As research continued it became apparent that these movements are inextricably linked with not only physical health but also mental and emotional health. Palpation of these tide-like motions allows Craniosacral therapists to facilitate change in areas of restriction. This restriction of movement corresponds to a lack of the capacity of the life force to express its self-healing." In reality, the bones of the skull start fusing in infancy and are completely solid by the teen years. More importantly, the cerebrospinal fluid has been shown not to have any measurable pulsation. With that in mind, I conclude that cranial manipulation would not be any more useful than a good massage. For more details, see this review article on craniosacral therapy.
Q: Is iron dangerous for children with DS?
A: The claim that iron is dangerous is often based on two suppositions, the first being that since iron is present in plaques in the brain of people with Alzheimer's disease, iron must be part of the process of the creation of the plaques. However, it has been shown that plaques in the brains of people with Alzheimer's disease are very sticky, and contain many things that may not have been involved in the initial formation of the plaques. Researchers have still not come to an agreement on exactly what causes the plaques, and how the plaques actually fit into the clinical picture of dementia. (Readers interested in more on this topic are advised to see the website of the Alzheimer Research Forum.)
The second supposition as to why iron might be harmful is based on the fact that people with DS have an excess amount of superoxide dismutase (SOD) in their cells, due to the extra 21st chromosome (see my essay on trisomy for more about this). The excess SOD is supposed to make more hydrogen peroxide available, which may react with iron to cause more damaging free radicals. At the present time, the research on this topic is still questionable and certainly ongoing. There is no definitive evidence that this happens, so it's too early to say that all iron is dangerous. I would certainly not recommend a low-iron formula for any infant with DS due to the high risk of iron deficiency anemia in this age group. After the second year of life, my personal recommendation would be that there's no reason to avoid iron-fortified foods, but there's no reason for extra iron supplementation in vitamins unless there is a documented anemia from iron deficiency. If you want to give your child a chewable vitamin and all your choices have some iron in them, pick the one with the lowest amount. (Caveat: women with DS who are menstruating do need iron supplementation to avoid becoming anemic; they don't tend to eat enough red meat to make up for the monthly blood loss.)
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