About 95 percent of the time, Down syndrome is caused by trisomy 21 — the person has three copies of chromosome 21, instead of the usual two copies, in all cells. This is caused by abnormal cell division during the development of the sperm cell or the egg cell. Mosaic Down syndrome.
What is Down syndrome associated with?
Down syndrome is a chromosomal condition that is associated with intellectual disability, a characteristic facial appearance, and weak muscle tone (hypotonia) in infancy. All affected individuals experience cognitive delays, but the intellectual disability is usually mild to moderate.
Is Down syndrome caused by mother or father?
There is no definitive scientific research that indicates that Down syndrome is caused by environmental factors or the parents’ activities before or during pregnancy. The additional partial or full copy of the 21st chromosome which causes Down syndrome can originate from either the father or the mother.
Which common anomaly is associated with Down syndrome?
Fourteen (2%) of the cases with DS had an obstructive anomaly of the renal pelvis, including hydronephrosis. The other most common anomalies associated with cases with DS were syndactyly, club foot, polydactyly, limb reduction, cataract, hydrocephaly, cleft palate, hypospadias and diaphragmatic hernia.
What is the history of Down syndrome?
It is named after British doctor John Langdon Down, who fully described the syndrome in 1866. Some aspects of the condition were described earlier by French psychiatrist Jean-Étienne Dominique Esquirol in 1838 and French physician Édouard Séguin in 1844. The genetic cause of Down syndrome was discovered in 1959.
What organ is most affected by Down syndrome?
Down syndrome, the most common chromosome-related genetic condition in the U.S., affects development of the brain and body. People with Down syndrome face physical and mental challenges, but can lead full and happy lives.
Can Down syndrome run in families?
In almost all cases, Down’s syndrome does not run in families. Your chance of having a baby with Down’s syndrome increases as you get older, but anyone can have a baby with Down’s syndrome.
What makes you high risk for Down’s syndrome baby?
One factor that increases the risk for having a baby with Down syndrome is the mother’s age. Women who are 35 years or older when they become pregnant are more likely to have a pregnancy affected by Down syndrome than women who become pregnant at a younger age.
Which parent is responsible for Down syndrome?
To date, no behavioral activity of the parents or environmental factor is known to cause Down syndrome. After much research on these cell division errors, researchers know that: In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.