Down Syndrome - Genetics Home Reference

Down syndrome is a genetic disorder that causesunusual looseness of the joints. Most children with
mental retardation and other problems. The conditionDown syndrome will have some, but not all, of these
varies in severity, so developmental problems mayfeatures.
range from mild to serious. Down syndrome is theThe degree of mental retardation varies widely from
most common genetic cause of severe learningmild to moderate to severe. However, most fall within
disabilities in children, occurring in one in every 700the mild to moderate range, and studies suggest that,
infants. Every year, as many as 6,000 babies are bornwith proper training, less than 10 percent will be
with Down syndrome in the United States. Theseverely mentally retarded.
condition is named after John Langdon Down, theDiagnosed
doctor who first identified the syndrome.Tests (such as amniocentesis and chorionic villus
There's no medical cure for this condition. Butsampling) can be done before birth to find out if a
increased understanding of Down syndrome and earlybaby has Down syndrome. Tissue and fluid in the
interventions make a big difference in the lives of bothwomb around the baby can be checked for the extra
children and adults with Down syndrome.chromosome. After birth, if the baby has any of the
Causes and Risk Factorsphysical signs or birth defects of Down syndrome, the
Down syndrome is one of the most common geneticbaby's blood can be tested to check for the extra
birth defects. It affects all races and economic levelschromosome.
equally. Approximately 1 in 800 to 1 in 1,000 babies areWhat's the treatment?
born with the disorder. Life expectancy among adultsThere's no cure, but treatment of any accompanying
with Down syndrome is about 55 years, though thishealth problems and support for learning difficulties
varies.allows many people with the syndrome to lead
Symptomsrelatively normal and semi-independent lives. Others,
A child with Down syndrome may have eyes thathowever, need full-time care. Many people with the
slant upward and small ears that may fold over a littlecondition live well into adulthood, with an average life
at the top. The mouth may be small, making theexpectancy of around 60 years.
tongue appear large. The nose also may be small, withPhysiotherapy, speech therapy and special educational
a flattened nasal bridge. Some babies with Downprogrammes have an important role to play, while
syndrome have short necks and small hands withspecific medical conditions associated with the
short fingers.syndrome are treated as appropriate.
The child with Down syndrome is often short and has