Describe what down syndrome is

Down syndrome is a condition in which a person has an extra chromosome. Typically, a baby is born with 46 chromosomes. Babies with Down syndrome have an extra copy of one of these chromosomes, chromosome Even though people with Down syndrome might act and look similar, each person has different abilities.

People with Down syndrome usually have an IQ a measure of intelligence in the mildly-to-moderately low range and are slower to speak than other children. Down syndrome remains the most common chromosomal condition diagnosed in the United States. Each year, about 6, babies born in the United States have Down syndrome.

This means that Down syndrome occurs in about 1 in every babies. There are three types of Down syndrome. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. Down Syndrome Also called: Trisomy Learn More Related Issues Genetics.

See, Play and Learn No links available. Resources Find an Expert. Start Here. However, healthcare professionals may recommend additional health screening for issues common to the condition. Early intervention can help a person maximize their potential and prepare them to take up an active role in the community. Physicians, special educators, speech therapists, occupational therapists, and physical therapists, as well as social workers, can all help.

The National Institute for Child Health and Human Development urge all specialists to provide stimulation and encouragement. Children with specific learning and development difficulties may be eligible for educational support, either in a mainstream or specialized school. In recent years, the tendency has been to attend mainstream schools, often with additional support to help them integrate and progress. The most common form of Down syndrome is called trisomy This is a condition wherein people have 47 chromosomes in each cell instead of An error in cell division called nondisjunction causes trisomy This error leaves a sperm or egg cell with an extra copy of chromosome 21 before or at conception.

This variant accounts for 95 percent of Down syndrome cases. The remaining 5 percent of Down syndrome cases are due to conditions called mosaicism and translocation. Mosaic Down syndrome occurs when some cells in the body are normal, while others have trisomy Robertsonian translocation occurs when part of chromosome 21 breaks off during cell division and attaches to another chromosome, usually chromosome The presence of this extra part of chromosome 21 causes some Down syndrome characteristics.

A person with a translocation does not have any special physical features, but they are more likely to have a child with an extra chromosome A person with Down syndrome can do many of the things that other people do. Children may take longer to acquire skills such as walking and talking, but with stimulation , they can acquire key life skills and attend school and, in some cases, college.

Depending on how the condition affects a person, it is often possible for someone to work and to live semi-independently with Down syndrome. Your support today helps make this vision a reality. Thank you! Prior to or at conception, a pair of 21st chromosomes in either the sperm or the egg fails to separate. As the embryo develops, the extra chromosome is replicated in every cell of the body. Mosaicism or mosaic Down syndrome is diagnosed when there is a mixture of two types of cells, some containing the usual 46 chromosomes and some containing Those cells with 47 chromosomes contain an extra chromosome Research has indicated that individuals with mosaic Down syndrome may have fewer characteristics of Down syndrome than those with other types of Down syndrome.

However, broad generalizations are not possible due to the wide range of abilities people with Down syndrome possess. The presence of the extra full or partial chromosome 21 causes the characteristics of Down syndrome. Regardless of the type of Down syndrome a person may have, all people with Down syndrome have an extra, critical portion of chromosome 21 present in all or some of their cells.

The cause of the extra full or partial chromosome is still unknown. Maternal age is the only factor that has been linked to an increased chance of having a baby with Down syndrome resulting from nondisjunction or mosaicism. The additional partial or full copy of the 21st chromosome which causes Down syndrome can originate from either the father or the mother. Down syndrome occurs in people of all races and economic levels, though older women have an increased chance of having a child with Down syndrome.

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