What are some of the effects of Down syndrome?

The effect of this extra DNA varies, but commonly people who have Down syndrome have mental disability, atypical facial structure, and physical defects, especially heart defects. They are at higher risk for developing leukemia, a thyroid problem, dementia or having trouble with their hearing or vision.

Reality: The average life expectancy for a person with Down syndrome is nearly 60 years old. Some people with Down syndrome have lived into their 80s. It is true that people with Down syndrome on average don’t live as long as their typical counterparts.

The most common mental health concerns include: general anxiety, repetitive and obsessive-compulsive behaviors; oppositional, impulsive, and inattentive behaviors; sleep related difficulties; depression; autism spectrum conditions; and neuropsychological problems characterized by progressive loss of cognitive skills.

Because Down syndrome is the result of a genetic anomaly, a cure is not possible at this time. While stories occasionally pop up about alleged gene therapy providing a cure, research is typically focused on addressing specific health concerns associated with Down syndrome.

A few of the common physical traits of Down syndrome are: low muscle tone, small stature, an upward slant to the eyes, and a single deep crease across the center of the palm. Every person with Down syndrome is a unique individual and may possess these characteristics to different degrees or not at all.

But children with Down Syndrome usually do develop the communication skills they need. During the early years of life, children with Down Syndrome are 10 to 15 times more likely than other children to develop leukemia, a disease that can be fatal.

There are three types of Down syndrome: trisomy 21 (nondisjunction), translocation and mosaicism.

Trisomy 21, the most common type of Down syndrome, occurs when there are three, rather than two, number 21 chromosomes present in every cell of the body.

Translocation accounts for 4% of all cases of Down syndrome.

DIAGNOSTIC PROCEDURES. The diagnostic procedures available for prenatal diagnosis of Down syndrome are chorionic villus sampling (CVS) and amniocentesis. These procedures, which carry up to a 1% risk of causing a spontaneous termination (miscarriage), are nearly 100% accurate in diagnosing Down syndrome.

Common physical signs of Down syndrome include1,2:

Decreased or poor muscle tone.

Short neck, with excess skin at the back of the neck.

Flattened facial profile and nose.

Small head, ears, and mouth.

Upward slanting eyes, often with a skin fold that comes out from the upper eyelid and covers the inner corner of the eye.

Down syndrome continues to be the most common chromosomal disorder. Each year, about 6,000 babies are born with Down syndrome, which is about 1 in every 700 babies born. Between 1979 and 2003, the number of babies born with Down syndrome increased by about 30%.

Diagnostic tests that can identify Down syndrome include: Chorionic villus sampling (CVS). In CVS, cells are taken from the placenta and used to analyze the fetal chromosomes. This test is typically performed in the first trimester, between 10 and 13 weeks of pregnancy.

60 years

The most common form of Down syndrome is known as trisomy 21, a condition where individuals have 47 chromosomes in each cell instead of 46. Trisomy 21 is caused by an error in cell division called nondisjunction. This leaves a sperm or egg cell with an extra copy of chromosome 21 before or at conception.

Diagnostic tests that can identify Down syndrome include: Amniocentesis – performed after week 15. Chorionic villus sampling (CVS) – performed between the 9th and 14th week. Percutaneous umbilical blood sampling (PUBS) – performed after week 18.

Screening tests are now standard in most prenatal care and can give parents an idea of the likelihood of chromosomal abnormalities. There are exceptions to all the above, and so not all cases can be prevented. Down syndrome cannot be prevented. It is a genetic abnormality that happens spontaneously.

But there is one key risk factor for Down syndrome: maternal age. A 25-year-old woman has a 1 in 1,200 chance of having a baby with Down syndrome; by 35, the risk has increased to 1 in 350; by age 40, to 1 in 100; and by 49, it’s 1 in 10, according to the National Down Syndrome Society.

Down syndrome (DS or DNS), also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with physical growth delays, characteristic facial features, and mild to moderate intellectual disability. The extra chromosome occurs by chance.

Down syndrome is one of the most common genetic birth defects, affecting approximately one in about 800 babies. In this country, around 250,000 individuals have Down syndrome. Life expectancy among adults with Down syndrome is about 60 years, though average lifespan varies.

Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells.

It is estimated that 1 in every 500 to 1,000 newborn males has an extra X chromosome, making Klinefelter syndrome one of the most common chromosomal disorders seen among newborns. Variants of Klinefelter syndrome (such as 48,XXXY, 49,XXXXY) are much rarer, occurring in 1 in 50,000 to 1 in 85,000 or fewer newborns.