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The process of studying chromosomes and describing them is called karyotyping. A karyotype determines whether Down syndrome is present and the type of chromosomal abnormality. A chromosome abnormality results whenever there is too much or too little chromosomal material. When an extra 21st chromosome is present in each of the body’s cells, it is called TRISOMY 21. Most individuals with Down syndrome have a complete free floating extra 21st chromosome and have 47 chromosomes in each cell. This occurs as a result of a mechanical accident in cell division during the production of the egg or sperm cell, called NO DISJUNCTION. Known as a TRANSLOCATION, occasionally the extra 21st chromosome is attached to or incorporated into another chromosome in the egg or sperm. The total chromosome number will be the normal 46 but there will still be Trisomy 21. In about half of these instances the translocation chromosome is inherited from one or the other normal parent. Spontaneous translocation may also occur. A child might instead have a MOSAIC chromosome make-up, some of their cells having extra chromosome material and others having a normal chromosome number. This results from the accident in cell division occurring in the developing embryo after the egg and sperm have united.

Q: What determines the risk for Down Syndrome?

A: Approximately 1 in 800 births result in a child with Down syndrome. Of all genetic disorders involving chromosomal problems Down syndrome has the highest prevalence. Approximately 5,000 children with Down syndrome are born each year in the U.S. A child with Down syndrome can be born to anyone, regardless of age, race or economic status. Eighty percent of children with Down syndrome are born to mothers less than 35 years of age, as more babies in general are born to younger mothers. The chance of giving birth to a baby with Down syndrome increases slightly for parents who already have a child with Down syndrome. Increased maternal age also increases risk from 1:400 at age 35 to 1:110 at age 40. 

Q: What are the physical characteristics of Down Syndrome?

A: Some of the physical characteristics of Down syndrome may be low muscle tone (hypotonia), oval-shaped eyes, epicanthal folds (small skin folds on the inner corner of the eye), single palmar creases (a straight line across the palm of the hand), reduced size of nose, flattened nasal bridge, a small oral cavity that may cause the tongue to protrude or appear larger and small ears that are sometimes folded slightly at the top. Most of these physical characteristics are not health problems. Not all of these characteristics are present in every person with Down syndrome. Each child is a unique individual who also resembles other family members. 

Q: What are some of the health problems that may occur in people with Down Syndrome?

A: Approximately 40 to 50% of children born with Down syndrome have congenital heart defects. There are several different forms of heart defects with varied degrees of seriousness associated with them. Surgical repair of these defects is being done with great success when the child is young. There is an increased incidence of respiratory problems, especially upper respiratory infections. Recent studies show that there are more eye and ear problems including a high incidence of fluctuating hearing loss in individuals with Down syndrome. Thyroid and cervical spine (atlanto-axial dislocation) abnormalities and gastro-intestinal problems may occur in persons with Down syndrome. Research indicates that all individuals with Down syndrome who live past age 35 will develop some physiologic signs of Alzheimer'’ disease, but not all develop the associated dementia. Leukemia risk increases 15-20 times with Down syndrome. Life expectancy among individuals with Down syndrome is approximately 55 years or longer. 

Q: What are the intellectual and social capabilities of a child with Down Syndrome?

A: Most individuals with Down syndrome have some degree of mental retardation. The degree of retardation can range from minimal to severe. The average person with Down syndrome functions in the mild to moderate range. They can be educated in public school, learn basic academic and work skills and perform many daily living activities independently. Many young adults with Down syndrome are employed in the community in a variety of jobs. As adults, an increasing number of persons with Down syndrome are living in group homes. People with Down syndrome date, socialize and form ongoing relationships. They may marry. Although it is rare, men with Down syndrome can father a child. Women with Down syndrome may have children. There is a 50% chance their child will have Down syndrome. A person with Down syndrome has the same emotions and needs as any other person. 

Q: Is there anyway to determine prior to birth if a child will have Down Syndrome?

A: Prenatal testing can diagnose or rule out Down Syndrome. Amniocentesis is usually performed about the 14th-16th week of pregnancy and involves removing a small amount of amniotic fluid from the uterus. Cells shed from the fetus are captured from the fluid, grown and screened for chromosomal makeup. A blood screening test called maternal serum alpha fetal protein testing (MSAFP) is now usually performed on pregnant women. This may be helpful to women in deciding whether to have amniocentesis. Abnormal measurements of AFP and two pregnancy hormones can also determine a woman’s risk of carrying a fetus with Down syndrome, however, these blood tests are only screening tools and do not provide a conclusive diagnosis. Chorionic villus sampling (CVS) is another test of chromosomal makeup. It is usually done at about the 9th-10th week of pregnancy and involves withdrawing a small amount of tissue from the developing placenta. The cells are then analyzed to determine the chromosomal status of the fetus. 

Q: Does early intervention make a difference in the life of a child with Down Syndrome?

A: Our experience and current research indicate that children with Down syndrome benefit from living with their family and interacting with all children. They also benefit from early intervention such as the Association for Children with Down Syndrome infant, toddler and preschool programs. Parent and infant education can begin immediately after birth. The individual child receives direct service programming to develop learning, language, gross and fine motor, socialization and self-help skills. Toddler and preschool programs further enhance the acquisition of skills to enable children with Down syndrome to reach their maximum potential. On-site day care and sibling programs foster inclusion. Early intervention, a stimulating home environment and good medical care all contribute to having a person with Down syndrome be an active contributing member of their community.

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 Sown Syndrome, and the risk and recurrence risk of Sown Syndrome. 

Q: Are adults with Down Syndrome sterile?

A: Women with Sown Syndrome are fertile. Men with Sown Syndrome have traditionally been considered sterile; however, there have been two documented cases of adult men with Sown Syndrome 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 Sown Syndrome than any other child. Fluoride in the proper amounts is not toxic. 

Q: Does fluoride intake increase the risk of having a child with Down Syndrome?

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 Sown Syndrome 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 Sown Syndrome, why are more than half of all babies with Down Syndrome born to women under 35 years?

A: While it is much more common for babies with Sown Syndrome 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 Down Syndrome?

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

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

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 Sown Syndrome 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 Sown Syndrome 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 Sown Syndrome 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 mental retardation is very difficult, and has been complicated by the fact that many medical conditions seen in adults with Sown Syndrome may mimic cognitive deterioration. So the true prevalence of Alzheimer's dementia in Sown Syndrome may not yet be known. 

Q: Are atropine eye drops dangerous for children with Down Syndrome?

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 Sown Syndrome 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 Sown Syndrome 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 Sown Syndrome 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 Sown Syndrome 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 Sown Syndrome 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 Sown Syndrome. A study from Europe in 1997 found that in babies born with Sown Syndrome, 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 Sown Syndrome 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 Down Syndrome?

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 Sown Syndrome 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 Sown Syndrome 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 Down Syndrome 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.)

ADHD  ||  Aspergers  ||  Autism  ||  Cerebral Palsy  ||  Down Syndrome