Amniocentesis (also referred to as amniotic fluid test or AFT), is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, in which a small amount of amniotic fluid, which contains fetal tissues, is extracted from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for genetic abnormalities
Tests of fetal cells found in this fluid can reveal the presence of Down syndrome or other chromosome problems in the baby. Amniocentesis can also show whether the lungs of the baby are mature enough to allow it to survive if it were elivered right away.
Amniocentesis is often recommended for pregnant women over age 35, women who have an abnormal “triple screen” blood test during pregnancy, or women who have (or whose husbands have) a family history of certain diseases or birth defects.
How do you prepare for the test?
You should have a serious discussion with your obstetrician regarding whether to have amniocentesis. Amniocentesis may be done anytime between the 14th and 20th weeks of pregnancy to test for fetal abnormalities. To check on fetal lung development, the test may be done late in the third trimester.
Tell your doctor ahead of time if you have ever had an allergic reaction to lidocaine or the numbing medicine used at the dentist’s office.
Just before the test, you should empty your bladder.
How the test is performed ?
Before the actual procedure, a local anesthetic is sometimes given to relieve the pain when inserting the needle used to withdraw the fluid. A needle is usually inserted through the mother’s abdominal wall through the wall of the uterus into the amniotic sac. With the aid of ultrasound-guidance, a physician aims towards an area of the sac that is away from the fetus and extracts approximately 20ml of amniotic fluid for testing. The puncture heals, and the amniotic sac replenishes the liquid over a day or so. After the amniotic fluid is extracted, the fetal cells are separated from it. The cells are grown in a culture medium, then fixed and stained. Under a microscope the chromosomes are examined for abnormalities. The most common abnormalities detected are Down syndrome, Edward syndrome [Trisomy 18] and Turner syndrome [Monosomy X]. Amniocentesis is most safely performed after the 14th-16th week of pregnancy, does not need to be done before then due to risk it can to to the babys limbs. Usually genetic counseling is offered prior to amniocentesis.
What happens when the test is performed?
You wear a hospital gown and lie on your back on a table. An ultrasound is done to show the location of the fetus and placenta. Your lower abdomen is cleaned with an antibacterial soap. In some cases, the doctor uses a small needle to inject a numbing medicine just under the skin, so you do not feel the amniocentesis sampling needle later. (Because the sampling needle does not cause much more stinging than the numbing medicine itself, not every doctor includes this step.)
The hollow sampling needle is several inches long and is inserted through the skin and abdominal muscle and then through the wall of the uterus. A syringe attached to the needle is used to collect a sample of fluid.
The baby’s heart tones and the mother’s blood pressure and heart rate are checked at the beginning and end of the procedure. The whole procedure takes close to 30 minutes.
Although the procedure is routine, possible complications include infection of the amniotic sac from the needle, and failure of the puncture to heal properly, which can result in leakage or infection. Serious complications can result in miscarriage. Other possible complications include preterm labor and delivery, respiratory distress, postural deformities, fetal trauma and alloimmunisation (rhesus disease). Studies from the 1970s originally estimated the risk of amniocentesis-related miscarriage at around 1 in 200 (0.5%). A more recent study (2006) has indicated this may actually be much lower, perhaps as low as 1 in 1,600 (0.06%). In contrast, the risk of miscarriage from chorionic villus sampling (CVS) is believed to be approximately 1 in 100, although CVS may be done up to four weeks earlier, and may be preferable if the possibility of genetic defects is thought to be higher
Most women experience a few hours of mild pelvic cramping, and a few will have slight vaginal bleeding. About 1 in 100 women will have a temporary leak of amniotic fluid through the vagina; this usually causes no problem.
There is a small risk of miscarriage associated with amniocentesis; this occurs in about 1 in every 200 to 400 cases, depending in part on the timing of the test and the experience level of the physician performing it. Other risks (such as infection or injury to the fetus that does not cause miscarriage) are extremely rare.
What must you do after the test is over?
If the test confirms that you are Rh incompatible with the fetus, you will need to receive an injection of a medicine called Rh immune globulin (Rhogam) to protect the baby from complications.
Let your doctor know immediately if you are having any vaginal bleeding, fluid leakage, or strong abdominal pain.
Time to know the result:
Chromosome analysis of the fluid sample takes two weeks or more. The results of some tests may be available sooner.
Amniocentesis and stem cells:
Recent studies discovered that in amniotic fluid there are a lot of multipotent stem cell, mesenchymal, hematopoietic, neural,epithelial and endothelial stem cell. Amniotic stem cells don’t have ethical problem. In fact, in harvesting embryonic stem cells, a human embryo is destroyed, and so it’s considered it immoral. Another potential benefit of using amniotic stem cells over those obtained from embryos is that they side-step ethical concerns among pro-life activists by obtaining pluripotent lines of undifferentiated cells without harm to a fetus or destruction of an embryo.
Artificial heart valves, working tracheas, as well as muscle, fat, bone, heart, neural and liver cells have all been engineered through use of amniotic stem cells . Tissues obtained from amniotic cell lines show enormous promise for patients suffering from congenital diseases/malformations of the heart, liver, lungs, kidneys, and cerebral tissue
Chromosomes are the units of genetic information that exist within every cell of the body. Twenty-three distinctive pairs, or 46 total chromosomes, are located within the nucleus (central structure) of each cell. When a baby is conceived by the combining of one sperm cell with one egg cell, the baby receives 23 chromosomes from each parent, for a total of 46 chromosomes. Sometimes, an accident in the production of a sperm or egg cell causes that cell to contain 24 chromosomes. This event is referred to as nondisjunction. When this defective cell is involved in the conception of a baby, that baby will have a total of 47 chromosomes. The extra chromosome in Down syndrome is labeled number 21. For this reason, the existence of three such chromosomes is sometimes referred to as Trisomy 21.
In a very rare number of Down syndrome cases (about 1–2%), the original egg and sperm cells are completely normal. The problem occurs sometime shortly after fertilization; during the phase where cells are dividing rapidly. One cell divides abnormally, creating a line of cells with an extra chromosome 21. This form of genetic disorder is called a mosaic. The individual with this type of Down syndrome has two types of cells: those with 46 chromosomes (the normal number), and those with 47 chromosomes (as occurs in Down syndrome). Some researchers have suggested that individuals with this type of mosaic form of Down syndrome have less severe signs and symptoms of the disorder.
Another relatively rare genetic accident which can cause Down syndrome is called translocation. During cell division, the number 21 chromosome somehow breaks. A piece of the 21 chromosome then becomes attached to another chromosome. Each cell still has 46 chromosomes, but the extra piece of chromosome 21 results in the signs and symptoms of Down syndrome. Translocations occur in about 3–4% of cases of Down syndrome.
Down syndrome occurs in about one in every 800–1,000 births. It affects an equal number of boys and girls. Less than 25% of Down syndrome cases occur due to an extra chromosome in the sperm cell. The majority of cases of Down syndrome occur due to an extra chromosome 21 within the egg cell supplied by the mother (nondisjunction). As a woman’s age (maternal age) increases, the risk of having a Down syndrome baby increases significantly. For example, at younger ages, the risk is about one in 4,000. By the time the woman is age 35, the risk increases to one in 400; by age 40 the risk increases to one in 110; and by age 45 the risk becomes one in 35. There is no increased risk of either mosaicism or translocation with increased maternal age.
Causes and Symptoms:-
While Down syndrome is a chromosomal disorder, a baby is usually identified at birth through observation of a set of common physical characteristics. Babies with Down syndrome tend to be overly quiet, less responsive, with weak, floppy muscles. Furthermore, a number of physical signs may be present. These include:
*flat appearing face
*flat bridge of the nose
*smaller than normal, low-set nose
*small mouth, which causes the tongue to stick out and to appear overly large
*upward slanting eyes
*extra folds of skin located at the inside corner of each eye, near the nose (called epicanthal folds)
*small, misshapen ears
*small, wide hands
*an unusual, deep crease across the center of the palm (called a simian crease)
*a malformed fifth finger
*a wide space between the big and the second toes
*unusual creases on the soles of the feet
*overly-flexible joints (sometimes referred to as being double-jointed)
*ahorter than normal height
Other types of defects often accompany Down syndrome. About 30–50% of all children with Down syndrome are found to have heart defects. A number of different heart defects are common in Down syndrome, including abnormal openings (holes) in the walls that separate the heart’s chambers (atrial septal defect, ventricular septal defect). These result in abnormal patterns of blood flow within the heart. The abnormal blood flow often means that less oxygen is sent into circulation throughout the body. Another heart defect that occurs in Down syndrome is called Tetralogy of Fallot. Tetralogy of Fallot consists of a hole in the heart, along with three other major heart defects.
Malformations of the gastrointestinal tract are present in about 5–7% of children with Down syndrome. The most common malformation is a narrowed, obstructed duodenum (the part of the intestine into which the stomach empties). This disorder, called duodenal atresia, interferes with the baby’s milk or formula leaving the stomach and entering the intestine for digestion. The baby often vomits forcibly after feeding, and cannot gain weight appropriately until the defect is repaired.
Other medical conditions that occur in patients with Down syndrome include an increased chance of developing infections, especially ear infections and pneumonia; certain kidney disorders; thyroid disease (especially low or hypothyroid); hearing loss; vision impairment requiring glasses (corrective lenses); and a 20-times greater chance of developing leukemia (a blood disorder).
Development in a baby and child with Down syndrome occurs at a much slower than normal rate. Because of weak, floppy muscles (hypotonia), babies learn to sit up, crawl, and walk much later than their normal peers. Talking is also quite delayed. The level of mental retardation is considered to be mild-to-moderate in Down syndrome. The actual IQ range of Down syndrome children is quite varied, but the majority of such children are in what is sometimes known as the trainable range. This means that most people with Down syndrome can be trained to do regular self-care tasks, function in a socially appropriate manner in a normal home environment, and even hold simple jobs.
As people with Down syndrome age, they face an increased chance of developing the brain disease called Alzheimer’s (sometimes referred to as dementia or senility). Most people have a six in 100 risk of developing Alzheimer’s, but people with Down syndrome have a 25 in 100 chance of the disease. Alzheimer’s disease causes the brain to shrink and to break down. The number of brain cells decreases, and abnormal deposits and structural arrangements occur. This process results in a loss of brain functioning. People with Alzheimer’s have strikingly faulty memories. Over time, people with Alzheimer’s disease will lapse into an increasingly unresponsive state. Some researchers have shown that even Down syndrome patients who do not appear to have Alzheimer’s disease have the same changes occurring to the structures and cells of their brains.
As people with Down syndrome age, they also have an increased chance of developing a number of other illnesses, including cataracts, thyroid problems, diabetes, and seizure disorders.
Diagnosis is usually suspected at birth, when the characteristic physical signs of Down syndrome are noted. Once this suspicion has been raised, genetic testing (chromosome analysis) can be undertaken in order to verify the presence of the disorder. This testing is usually done on a blood sample, although chromosome analysis can also be done on other types of tissue, including skin. The cells to be studied are prepared in a laboratory. Chemical stain is added to make the characteristics of the cells and the chromosomes stand out. Chemicals are added to prompt the cells to go through normal development, up to the point where the chromosomes are most visible, prior to cell division. At this point, they are examined under a microscope and photographed. The photograph is used to sort the different sizes and shapes of chromosomes into pairs. In most cases of Down syndrome, one extra chromosome 21 will be revealed. The final result of such testing, with the photographed chromosomes paired and organized by shape and size, is called the individual’s karyotype.
Two types of prenatal tests are used to detect Down syndrome in a fetus: screening tests and diagnostic tests. Screening tests estimate the risk that a fetus has DS; diagnostic tests can tell whether the fetus actually has the condition.
Screening tests are cost-effective and easy to perform. But because they can’t give a definitive answer as to whether a baby has DS, these tests are used to help parents decide whether to have more diagnostic tests.
Diagnostic tests are about 99% accurate in detecting Down syndrome and other chromosomal abnormalities. However, because they’re performed inside the uterus, they are associated with a risk of miscarriage and other complications.
For this reason, invasive diagnostic testing previously was generally recommended only for women age 35 or older, those with a family history of genetic defects, or those who’ve had an abnormal result on a screening test.
However, the American College of Obstetrics and Gynecology (ACOG) now recommends that all pregnant women be offered screening with the option for invasive diagnostic testing for Down syndrome, regardless of age.
If you’re unsure about which test, if any, is right for you, your doctor or a genetic counselor can help you sort through the pros and cons of each.
Screening tests include:-
*Nuchal translucency testing. This test, performed between 11 and 14 weeks of pregnancy, uses ultrasound to measure the clear space in the folds of tissue behind a developing baby’s neck. (Babies with DS and other chromosomal abnormalities tend to accumulate fluid there, making the space appear larger.) This measurement, taken together with the mother’s age and the baby’s gestational age, can be used to calculate the odds that the baby has DS. Nuchal translucency testing is usually performed along with a maternal blood test.
*The triple screen or quadruple screen (also called the multiple marker test). These tests measure the quantities of normal substances in the mother’s blood. As the names imply, triple screen tests for three markers and quadruple screen includes one additional marker and is more accurate. These tests are typically offered between 15 and 18 weeks of pregnancy.
*Integrated screen. This uses results from first trimester screening tests (with or without nuchal translucency) and blood tests with second trimester quad screen to come up with the most accurate screening results.
*A genetic ultrasound. A detailed ultrasound is often performed at 18 to 20 weeks in conjunction with the blood tests, and it checks the fetus for some of the physical traits abnormalities associated with Down syndrome.
Diagnostic tests include:-
*Chorionic villus sampling (CVS). CVS involves taking a tiny sample of the placenta, either through the cervix or through a needle inserted in the abdomen. The advantage of this test is that it can be performed during the first trimester, between 8 and 12 weeks. The disadvantage is that it carries a slightly greater risk of miscarriage as compared with amniocentesis and has other complications.
*Amniocentesis. This test, performed between 15 and 20 weeks of pregnancy, involves the removal of a small amount of amniotic fluid through a needle inserted in the abdomen. The cells can then be analyzed for the presence of chromosomal abnormalities. Amniocentesis carries a small risk of complications, such as preterm labor and miscarriage.
*Percutaneous umbilical blood sampling (PUBS). Usually performed after 20 weeks, this test uses a needle to retrieve a small sample of blood from the umbilical cord. It carries risks similar to those associated with amniocentesis.
After a baby is born, if the doctor suspects DS based on the infant’s physical characteristics, a karyotype — a blood or tissue sample stained to show chromosomes grouped by size, number, and shape — can be performed to verify the diagnosis.
No treatment is available to cure Down syndrome. Treatment is directed at addressing the individual concerns of a particular patient. For example, heart defects will many times require surgical repair, as will duodenal atresia. Many Down syndrome patients will need to wear glasses to correct vision. Patients with hearing impairment benefit from hearing aids.
At one time, most children with Down syndrome did not live past childhood. Many would often become sick from infections. Others would die from their heart problems or other problems they had at birth. Today, most of these health problems can be treated and most children who have it will grow into adulthood.
Medicines can help with infections and surgery can correct heart, stomach, and intestinal problems. If the person gets leukaemia, there are medical treatments that can be very successful. Someone with Down syndrome has a good chance of living to be 50 years old or more.
A new drug, referred to as a “smart drug,” has been receiving some attention in the treatment of Down syndrome patients. This drug, piracetam, has not been proven to increase intellectual ability, despite testimonials that have been receiving attention on television and the Internet. Piracetam has not been approved for use in the United States, although it is being sold via the Internet. The National Down Syndrome Society and the National Down Syndrome Congress do not recommend the use of this drug as of 2001.
While some decades ago, all Down syndrome children were quickly placed into institutions for lifelong care. Research shows very clearly that the best outlook for children with Down syndrome is a normal family life in their own home. This requires careful support and education of the parents and the siblings. It is a life-changing event to learn that a new baby has a permanent condition that will effect essentially all aspects of his or her development. Some community groups exist to help families deal with the emotional effects of this new information, and to help plan for the baby’s future. Schools are required to provide services for children with Down syndrome, sometimes in separate special education classrooms, and sometimes in regular classrooms (this is called mainstreaming or inclusion).
The prognosis in Down syndrome is quite variable, depending on the types of complications (heart defects, susceptibility to infections, development of leukemia) of each individual baby. The severity of the retardation can also vary significantly. Without the presence of heart defects, about 90% of children with Down syndrome live into their teens. People with Down syndrome appear to go through the normal physical changes of aging more rapidly, however. The average age of death for an individual with Down syndrome is about 50–55 years.
Still, the prognosis for a baby born with Down syndrome is better than ever before. Because of modern medical treatments, including antibiotics to treat infections and surgery to treat heart defects and duodenal atresia, life expectancy has greatly increased. Community and family support allows people with Down syndrome to have rich, meaningful relationships. Because of educational programs, some people with Down syndrome are able to hold jobs.
Men with Down syndrome appear to be uniformly sterile (meaning that they are unable to have offspring). Women with Down syndrome, however, are fully capable of having babies. About 50% of these babies, however, will also be born with Down syndrome.
Efforts at prevention of Down syndrome are aimed at genetic counseling of couples who are preparing to have babies. A counselor needs to inform a woman that her risk of having a baby with Down syndrome increases with her increasing age. Two types of testing is available during a pregnancy to determine if the baby being carried has Down syndrome.
Screening tests are used to estimate the chance that an individual woman will have a baby with Down syndrome. At 14–17 weeks of pregnancy, measurements of a substance called AFP (alpha-fetoprotein) can be performed. AFP is normally found circulating in the blood of a pregnant woman, but may be unusually high or low with certain disorders. Carrying a baby with Down syndrome often causes AFP to be lower than normal. This information alone, or along with measurements of two other hormones, is considered along with the mother’s age to calculate the risk of the baby being born with Down syndrome. These results are only predictions, and are only correct about 60% of the time.
The only way to definitively establish (with about 98–99% accuracy) the presence or absence of Down syndrome in a developing baby, is to test tissue from the pregnancy itself. This is usually done either by amniocentesis or chorionic villus sampling (CVS). In amniocentesis, a small amount of the fluid in which the baby is floating is withdrawn with a long, thin needle. In chorionic villus sampling, a tiny tube is inserted into the opening of the uterus to retrieve a small sample of the placenta (the organ that attaches the growing baby to the mother via the umbilical cord, and provides oxygen and nutrition). Both amniocentesis and CVS allow the baby’s own karyotype to be determined. A couple must then decide whether to use this information in order to begin to prepare for the arrival of a baby with Down syndrome, or to terminate the pregnancy.
Once a couple has had one baby with Down syndrome, they are often concerned about the likelihood of future offspring also being born with the disorder. Most research indicates that this chance remains the same as for any woman at a similar age. However, when the baby with Down syndrome has the type that results from a translocation, it is possible that one of the two parents is a carrier of that defect. A carrier “carries” the genetic defect, but does not actually have the disorder. When one parent is a carrier of a translocation, the chance of future offspring having Down syndrome is greatly increased. The specific risk will have to be calculated by a genetic counselor.
Main article: Research of Down syndrome-related genes
Down syndrome is “a developmental abnormality characterized by trisomy of human chromosome 21″ (Nelson 619). The extra copy of chromosome-21 leads to an over expression of certain genes located on chromosome-21.
Research by Arron et al shows that some of the phenotypes associated with Down Syndrome can be related to the dysregulation of transcription factors (596), and in particular, NFAT. NFAT is controlled in part by two proteins, DSCR1 and DYRK1A; these genes are located on chromosome-21 (Epstein 582). In people with Down Syndrome, these proteins have 1.5 times greater concentration than normal (Arron et al. 597). The elevated levels of DSCR1 and DYRK1A keep NFAT primarily located in the cytoplasm rather than in the nucleus, preventing NFATc from activating the transcription of target genes and thus the production of certain proteins (Epstein 583).
This dysregulation was discovered by testing in transgenic mice that had segments of their chromosomes duplicated to simulate a human chromosome-21 trisomy (Arron et al. 597). A test involving grip strength showed that the genetically modified mice had a significantly weaker grip, much like the characteristically poor muscle tone of an individual with Down Syndrome (Arron et al. 596). The mice squeezed a probe with a paw and displayed a .2 newton weaker grip (Arron et al. 596). Down syndrome is also characterized by increased socialization. When modified and unmodified mice were observed for social interaction, the modified mice showed as much as 25% more interactions as compared to the unmodified mice (Arron et al. 596).
The genes that may be responsible for the phenotypes associated may be located proximal to 21q22.3. Testing by Olson et al. in transgenic mice show the duplicated genes presumed to cause the phenotypes are not enough to cause the exact features. While the mice had sections of multiple genes duplicated to approximate a human chromosome-21 triplication, they only showed slight craniofacial abnormalities (688-690). The transgenic mice were compared to mice that had no gene duplication by measuring distances on various points on their skeletal structure and comparing them to the normal mice (Olson et al. 687). The exact characteristics of Down Syndrome were not observed, so more genes involved for Down Syndrome phenotypes have to be located elsewhere.
Reeves et al, using 250 clones of chromosome-21 and specific gene markers, were able to map the gene in mutated bacteria. The testing had 99.7% coverage of the gene with 99.9995% accuracy due to multiple redundancies in the mapping techniques. In the study 225 genes were identified (311-313).
The search for major genes that may be involved in Down syndrome symptoms is normally in the region 21q21–21q22.3. However, studies by Reeves et al. show that 41% of the genes on chromosome-21 have no functional purpose, and only 54% of functional genes have a known protein sequence. Functionality of genes was determined by a computer using exon prediction analysis (312). Exon sequence was obtained by the same procedures of the chromosome-21 mapping.
Research has led to an understanding that two genes located on chromosome-21, that code for proteins that control gene regulators, DSCR1 and DYRK1A can be responsible for some of the phenotypes associated with Down Syndrome. DSCR1 and DYRK1A cannot be blamed outright for the symptoms; there are a lot of genes that have no known purpose. Much more research would be needed to produce any appropriate or ethically acceptable treatment options.
Recent use of transgenic mice to study specific genes in the Down syndrome critical region has yielded some results. APP is an Amyloid beta A4 precursor protein. It is suspected to have a major role in cognitive difficulties. Another gene, ETS2 is Avian Erythroblastosis Virus E26 Oncogene Homolog 2. Researchers have “demonstrated that over-expression of ETS2 results in apoptosis. Transgenic mice over-expressing ETS2 developed a smaller thymus and lymphocyte abnormalities, similar to features observed in Down syndrome.”
Vitamin supplements, in particular supplemental antioxidants and folinic acid, have been shown to be ineffective in the treatment of Down syndrome.
Sociological and cultural aspects:-
Advocates for people with Down syndrome point to various factors, such as additional educational support and parental support groups to improve parenting knowledge and skills. There are also strides being made in education, housing, and social settings to create environments which are accessible and supportive to people with Down syndrome. In most developed countries, since the early twentieth century many people with Down syndrome were housed in institutions or colonies and excluded from society. However, since the early 1960s parents and their organizations (such as MENCAP), educators and other professionals have generally advocated a policy of inclusion, bringing people with any form of mental or physical disability into general society as much as possible. In many countries, people with Down syndrome are educated in the normal school system; there are increasingly higher-quality opportunities to move from special (segregated) education to regular education settings.
Despite these changes, the additional support needs of people with Down syndrome can still pose a challenge to parents and families. Although living with family is preferable to institutionalization, people with Down syndrome often encounter patronizing attitudes and discrimination in the wider community.
The first World Down Syndrome Day was held on 21 March 2006. The day and month were chosen to correspond with 21 and trisomy respectively. It was proclaimed by European Down Syndrome Association during their European congress in Palma de Mallorca (febr. 2005). In the United States, the National Down Syndrome Society observes Down Syndrome Month every October as “a forum for dispelling stereotypes, providing accurate information, and raising awareness of the potential of individuals with Down syndrome.” In South Africa, Down Syndrome Awareness Day is held every October 20. Organizations such as Special Olympics Hawaii provide year-round sports training for individuals with intellectual disabilities such as down syndrome.
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.
India‘s urban elite has plenty of DINKs (Double Income, No Kids). These people get married later than their rural counterparts, often after they are financially and professionally independent and secure. They can afford the best, as far as pregnancy, antenatal care and delivery are concerned. Eventually, they limit their families to one or maybe two children for whom they wish to provide the best opportunities in life.
Under these circumstances, the birth of a child with Down’s Syndrome (trisomy 21 or mongolism) becomes an unbearable tragedy.
One in 800 children is born with Down’s Syndrome. Such children have a characteristic mongoloid appearance at birth itself, irrespective of the parents’ ethnic backgrounds. The head may be smaller than normal with a sloping forehead, upward slanting eyes, a small flattened nose, low set ears, short stumpy fingers, a protuberant abdomen and a tongue which sticks out of a small mouth. Also, the palm shows just two lines instead of the usual three.
Down’s Syndrome usually occurs spontaneously as a result of an anomaly during early embryonic cell proliferation producing an abnormal chromosome 21. During cell division it may have divided abnormally, producing three parts instead of the normal two. Sometimes a piece from the chromosome may have attached (translocated) itself to another chromosome.
These anomalies are more likely with increased maternal age at the time of the pregnancy. Many doctors and researchers consider the age 35 as the cut off.
The child shows all the typical features of Downâ€™s Syndrome if all the cells contain the abnormal chromosomes. Sometimes the person may be a mosaic, with a mixture of normal and abnormal cells. The appearance may then be atypical.
The risk of recurrence is greater if the condition has arisen as a result of translocation. This is because one of the parents is then likely to be a carrier. The risk is around 3 per cent if the father is the carrier, and 12 per cent if the mother carries the abnormal gene. Also, a mother with a Downâ€™s Syndrome child has a one per cent chance of producing another similarly affected child.
Life is difficult for children suffering from Downâ€™s Syndrome as they often have subnormal intelligence. They may also have abnormalities in other organs like the heart. There may be blocks or malfunction of the gastrointestinal tract with constipation and intestinal bloating. Hearing loss or visual defects may also occur. The chromosomal abnormality causes a decreased immune response, causing frequent infections as the children grow. The incidence of leukaemia is 20 times greater than in the general population. Dementia too sets in during early adult life (around 40). All this means a lifetime of nurturing and extra care.
So does this mean that women should sacrifice education and professional careers for early marriage and childbirth?
Not really, as advances in medical science have made it possible to diagnose Downâ€™s Syndrome during the antenatal period itself.
Ultrasound examination during the first trimester has a detection rate of approximately 95 per cent of all Down’s Syndrome cases. The measurement of nuchal translucency â€” the size of a collection of fluid at the base of the foetal neck correlates with the risk of Downs Syndrome. Other markers like the size of the head, the nose, the presence or absence of heart and intestinal defects can be evaluated with a scan. The presence of several abnormal markers may be an indication of Down’s Syndrome.
Moreover, certain blood tests performed on the mother can show abnormal results if the foetus is affected. Of these, the one commonly available in India is the alpha-fetoprotein level which tends to be less than normal in Down’s Syndrome.
To confirm the diagnosis, the chromosomes of the foetus can be examined. This can be done with amniocentesis (an examination of the cells in the amniotic fluid that surrounds the baby in the uterus). The diagnosis takes two weeks.
The cells of the placenta can be also tested during the 10th and 12th weeks of pregnancy by Chorionic Villus Sampling (CVS). If a rapid diagnosis is required, Percutaneous Umbilical Blood Sampling (PUBS) can be done after 18 weeks of gestation. Each of these three tests is 98 to 99 per cent accurate in diagnosing Down’s Syndrome. However, all these tests carry a risk of miscarriage.
After birth, Down’s Syndrome is suspected because of the typical appearance of the baby. It is confirmed by karyotyping or checking the baby’s chromosomes to demonstrate the extra chromosome in the cells.
Unfortunately, much of this high-tech diagnosis is out of reach for the average Indian woman. Financial constraints, poor education and lack of facilities are major drawbacks to good antenatal care and prenatal diagnosis.
The new chemical, calledFDDNP, attaches to abnormal clumps of proteins called amyloid plaques and nerve cell tangles that develop in Alzheimer’s sufferers and inhibit messages being processed by the brain.
In the study, Dr. Gary Small and his colleagues discovered that the chemical allowed doctors to pick out which of 83 volunteers had Alzheimer’s, which had mild memory problems and which were functioning normally for their age.
It was 98 percent accurate in determining the difference between Alzheimer’s and mild cognitive impairment, which surpassed the 87 percent success rate for a PET scan test that measured sugar metabolism in the brain, and the 62 percent accuracy rate when doctors used a magnetic resonance imaging.
The FDDNP signal can be seen in people years before they develop Alzheimer’s disease, Dr. Small said.
Finding an easier way to track brain deterioration would also make it easier to assess experimental treatments, as researchers try to prevent or reduce the accumulation of plaques and tangles.
Dr. Small and 4 of the other 15 authors named in the research paper have a financial interest in FDDNP, which has been licensed to the German conglomerate Siemens AG. He said he hoped to see it on the market in three years.
About 4.5 million people in the United States have Alzheimer’s, a number that is expected to grow as the population ages. About 15 million to 20 million more have the mild cognitive impairment that often leads to the disease.
Alzheimer’s disease is a progressive brain disorder that gradually destroys a person’s memory and ability to learn, reason, make judgments, communicate and carry out daily activities. As Alzheimer’s progresses, individuals may also experience changes in personality and behavior, such as anxiety, suspiciousness or agitation, as well as delusions or hallucinations.
“Dementia“ simply means the symptom of a deterioration of intellectual abilities resulting from an unspecified disease or disorder of the brain.Dementia can best be defined as one of the symtoms of Alzheimer’s disease.
Alzheimers Disease is one disease/disorder that causes dementia. Many other illnesses or “syndromes” can also cause dementia. Parkinsons Disease can cause dementia. A stroke can cause dementia. Even dehydration can cause dementia...CLICK & SEE
When people think about staying fit, they generally think from the neck down. But the health of your brain plays a critical role in almost everything you do: thinking, feeling, remembering, working, and playing “ and even sleeping.He can be called a fit person who is perfect in body,mind and sole.
There are two basic types of Alzheimer’s disease: Early-onset Alzheimer’s disease tends to strike people under age 65 and is more likely to run in families. Late-onset Alzheimer’s disease, the much more common type, generally afflicts people after age 65. The exact cause of Alzheimer’s is unknown, although researchers studying this puzzling disease are making progress.
Who Is Affected?
The chances of getting Alzheimer’s disease increase with age. It usually occurs after age 65. Most people are not affected even at advanced ages. Research indicates that there are two definite factors which may increase the risk for Alzheimer’s disease: a family history of dementia and Down’s syndrome.
Family History of Dementia
Some forms of Alzheimer’s disease are inherited. If Alzheimer’s disease has occurred in your family members, other members are more likely to develop it.
Persons with Down’s syndrome have a higher chance of getting Alzheimer’s disease. Close relatives of persons with Down’s syndrome also may be at risk
The good news is that we now know thereâ€™s a lot you can do to help keep your brain healthier as you age. These steps might also reduce your risk of Alzheimerâ€™s disease or other dementia.
Simple lifestyle modifications also would have an enormous impact on our public health and the cost of healthcare woul be reduced. If you make brain-healthy lifestyle changes and take action by getting involved, we could realize a future without Alzheimer’s disease.
1.Try to make you brain healthy and keep you happy in most of your actions.
Like other parts of your body, your brain may lose some agility as you get older. It can deteriorate even more if you donâ€™t take care of it. Science is unlocking many of the mysteries of the brain, but we donâ€™t have all the answers yet.
2.Stay mentally active
This will strengthen your brain cells and improve connections between them.
3. Stay physically active
This will increase the blood flow to the brain as well as encourage new new brain cells.
4. Always try to eat healthy diet.
Research suggests that high cholesterol may contribute to stroke and brain cell damage. A low fat, low cholesterol diet is advisable. And there is growing evidence that a diet rich in dark vegetables and fruits, which contain antioxidants, may help protect brain cells.
I personally believe that regular practice of YOGA and MEDITATION this type of disease can be kept under total control and particularlyPRANAYAM is very good for this.
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.