History of down syndrome

History of down syndrome

Screening for Down syndrome is offered as a routine part of prenatal care. A mother's age has traditionally been a factor in the decision to screen for Down syndrome. But now, the American Congress of Obstetricians and Gynecologists recommends offering various screening tests for Down syndrome to all pregnant women, regardless of age. Although screening tests aren't perfect, they can help you make decisions about more-invasive diagnostic tests and the course of the pregnancy.

If your baby is diagnosed before birth with Down syndrome, you'll also have more time to prepare for caring for a child with special needs. Your health care provider can help you weigh the pros and cons of these tests. Screening tests during pregnancy Various screening tests can help identify whether you have a high risk of carrying a baby with Down syndrome. In the past, blood tests typically have been offered around the 16th week of pregnancy to screen for Down syndrome, spina bifida and various other chromosomal disorders. Currently, more women are electing the first trimester combined test, done in two steps during week 11 to 13 of pregnancy. 

The first trimester combined test includes:
Ultrasound. The doctor uses ultrasound to measure a specific region on the back of a baby's neck. This is known as a nuchal translucency screening test. When abnormalities are present, more fluid than usual tends to collect in this tissue. Blood tests. Results of the ultrasound are paired with blood tests that measure levels of pregnancy-associated plasma protein-A (PAPP-A) and a hormone known as human chorionic gonadotropin (HCG). Abnormal levels of PAPP-A and HCG may indicate a problem with the baby.

If early assessment isn't your first priority, you can have full integrated testing, which is done in two parts during the first two trimesters of your pregnancy. The results of the two parts are combined to estimate the risk that your baby has Down syndrome. This test can achieve the same level of detection as the first trimester combined test but with a lower false-positive rate, meaning that fewer women are incorrectly identified as carrying a baby with Down syndrome. First trimester. Part one includes an ultrasound to measure nuchal translucency and a blood test to measure PAPP-A. Second trimester.

Done at 15 to 20 weeks of pregnancy, the quad screen measures your blood level of four pregnancy-associated substances, alpha fetoprotein, estriol, HCG and inhibin A. Of all the women who undergo screening tests for Down syndrome, about 5 percent are identified as being at risk. But the overall risk of Down syndrome among pregnant women is far below 5 percent. So the screening tests, by design, are much better at identifying women who may be at risk of having a baby with Down syndrome than women who actually have a baby with Down syndrome.

 CLICK HERE FOR TREATMENTS AND DRUGS

How is down syndrome diagnosed

 How is down syndrome diagnosed

Human cells normally contain 23 pairs of chromosomes. One chromosome in each pair comes from your father, the other from your mother. Down syndrome results when one of three types of abnormal cell division involving chromosome 21 occurs. All three cell division abnormalities result in extra genetic material from chromosome 21, which is responsible for the characteristic features and developmental problems of Down syndrome.

The three genetic variations that can cause Down syndrome include: Trisomy 21. More than 90 percent of the time, Down syndrome is caused by trisomy 21. A child with trisomy 21 has three copies of chromosome 21 — instead of the usual two copies — in all of his or her cells. This form of Down syndrome is caused by abnormal cell division during the development of the sperm cell or the egg cell. Mosaic Down syndrome.

In this rare form of Down syndrome, children have some cells with an extra copy of chromosome 21. This mosaic of normal and abnormal cells is caused by abnormal cell division after fertilization. Translocation Down syndrome. Down syndrome can also occur when part of chromosome 21 becomes attached (translocated) onto another chromosome, before or at conception. Children with translocation Down syndrome have the usual two copies of chromosome 21, but they also have additional material from chromosome 21 attached to the translocated chromosome.

This form of Down syndrome is uncommon. There are no known behavioral or environmental factors that cause Down syndrome. Is it inherited? Most of the time, Down syndrome isn't inherited. It's caused by a mistake in cell division during the development of the egg, sperm or embryo. Translocation Down syndrome is the only form of the disorder that can be passed from parent to child. However, only about 4 percent of children with Down syndrome have translocation.

And only about half of these children inherited it from one of their parents. When translocations are inherited, the mother or father is a balanced carrier of the translocation, which means he or she has some rearranged genetic material, but no extra genetic material. A balanced carrier has no signs or symptoms of Down syndrome, but he or she can pass the translocation on to children. The chance of passing on the translocation depends on the sex of the parent who carries the rearranged chromosome 21: If the father is the carrier, the risk is about 3 percent. If the mother is the carrier, the risk is between 10 and 15 percent.

 CLICK HERE FOR TREATMENTS AND DRUGS