What does down syndrome do

In all cases of reproduction, both parents pass their genes on to their children. These genes are carried in chromosomes. Half of the chromosomes are from the mother, and half are from the father. The baby ends up with three copies, or an extra partial copy, of chromosome 21, instead of two. This extra chromosome causes problems as the brain and physical features develop. This is the most common form of Down syndrome. Mosaicism occurs when a child is born with an extra chromosome in some but not all of their cells.

People with mosaic Down syndrome tend to have fewer symptoms than those with trisomy In this type of Down syndrome, children have only an extra part of chromosome There are 46 total chromosomes. However, one of them has an extra piece of chromosome 21 attached. Certain parents have a greater chance of giving birth to a child with Down syndrome. According to the Centers for Disease and Prevention, mothers aged 35 and older are more likely to have a baby with Down syndrome than younger mothers.

The probability increases the older the mother is. Research shows that paternal age also has an effect. Some of the more common health problems among children with Down syndrome are listed below.

Down syndrome is a lifelong condition. Services early in life will often help babies and children with Down syndrome to improve their physical and intellectual abilities. Most of these services focus on helping children with Down syndrome develop to their full potential. These services include speech, occupational, and physical therapy, and they are typically offered through early intervention programs in each state.

Children with Down syndrome may also need extra help or attention in school, although many children are included in regular classes. The views of these organizations are their own and do not reflect the official position of CDC. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

Birth Defects. A 35 year old woman has about a one in chance of conceiving a child with Down syndrome, and this chance increases gradually to 1 in by age At age 45 the incidence becomes approximately 1 in The age of the mother does not seem to be linked to the risk of translocation. Since many couples are postponing parenting until later in life, the incidence of Down syndrome conceptions is expected to increase.

Therefore, genetic counseling for parents is becoming increasingly important. Still, many physicians are not fully informed about advising their patients about the incidences of Down syndrome, advancements in diagnosis, and the protocols for care and treatment of babies born with Down syndrome. Heredity is not a factor in trisomy 21 nondisjunction and mosaicism.

Most cases are sporadic — chance — events. However, in about one-third of cases, one parent is a carrier of a translocated chromosome. Once a woman has given birth to a baby with trisomy 21 nondisjunction or translocation, it is estimated that her chances of having another baby with trisomy 21 is 1 in up until age Genetic counseling can determine the origin of translocation.

There are two categories of tests for Down syndrome that can be performed before a baby is born: screening tests and diagnostic tests. Prenatal screens estimate the chance of the fetus having Down syndrome.

These tests do not tell you for sure whether your fetus has Down syndrome; they only provide a probability. There is an extensive menu of prenatal screening tests now available for pregnant women. Most screening tests involve a blood test and an ultrasound sonogram. The blood tests or serum screening tests measure quantities of various substances in the blood of the mother.

New advanced prenatal screens are now able to detect chromosomal material from the fetus that is circulating in the maternal blood. These tests are not invasive like the diagnostic tests below , but they provide a high accuracy rate. Still, all of these screens will not definitively diagnose Down syndrome. Prenatal screening and diagnostic tests are now routinely offered to women of all ages. The diagnostic procedures available for prenatal diagnosis of Down syndrome are chorionic villus sampling CVS and amniocentesis.

Amniocentesis is usually performed in the second trimester between 15 and 20 weeks of gestation, CVS in the first trimester between 9 and 14 weeks. Down syndrome is usually identified at birth by the presence of certain physical traits: low muscle tone, a single deep crease across the palm of the hand, a slightly flattened facial profile and an upward slant to the eyes.

National Library of Medicine. Down syndrome. Genetics Home Reference. Facts about Down syndrome. Centers for Disease Control and Prevention. Frequently asked questions. Prenatal genetic diagnostic tests. American College of Obstetricians and Gynecologists. Ostermaier KK. Down syndrome: Management. Down syndrome: Clinical features and diagnosis. Accessed Jan. Gabbe SG, et al. Genetic screening and prenatal genetic diagnosis. In: Obstetrics: Normal and Problem Pregnancies.

Philadelphia, Pa. Rink BD, et al. Screening for fetal aneuploidy. Seminars in Perinatology. Bunt CW, et al. The role of the family physician in the care of children with Down syndrome.