In the majority of cases, the extra copy of
It is well known that the extra chromosome 21 originates from the mother in more than 90% of cases, the incidence increases with maternal age and there is a high recurrence in young women.
However, most children with Down syndrome are born to women under age 35 because younger women have far more babies. Being carriers of the genetic translocation for Down syndrome. Both men and women can pass the genetic translocation for Down syndrome on to their children.
Here's what the algorithm doesn't account for: Extra genetic material can also attach itself to chromosome 21 in the sperm. Scientists agree that Down syndrome can be attributed to the father in 5 to 10 percent of cases, and some believe that number may be as high as 20 percent.
A mother's age at her child's birth is the only factor linked to the risk of having a baby with Down syndrome. This risk increases with each year of age, especially after age 35. There is no reason to believe parents can do anything to cause or prevent Down syndrome in their child.
Down syndrome occurs in people of all races and economic levels. The risk increases with the mother's age (1 in 1250 for a 25 year old mother to 1 in 1000 at age 31, 1 in 400 at age 35, and about 1 in 100 at age 40). However, 80% of babies with Down syndrome are born to women under age 35 years.
Current supplementation policies designed to prevent neural tube defects may incidentally prevent Down's syndrome, provided a sufficiently high dose of folic acid is used.
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. Speak to a GP if you want to find out more. They may be able to refer you to a genetic counsellor.
These factors include geographic region, maternal education, marital status, and Hispanic ethnicity. Because the likelihood that an egg will contain an extra copy of chromosome 21 increases significantly as a woman ages, older women are much more likely than younger women to give birth to an infant with 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.
Inheritance. 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.
Babies: 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.
All men inherit a Y chromosome from their father, which means all traits that are only found on the Y chromosome come from dad, not mom. The Supporting Evidence: Y-linked traits follow a clear paternal lineage.
A known risk factor for Down syndrome is increasing maternal age. As seen in Figure 4, women who are 35 to 39 years old are approximately 4.5 times more likely to have a child with Down syndrome compared with women in the 25 to 29 age group. This risk increases to 15.7 for mothers age 40 years or older.
Down syndrome incidence in humans increases dramatically with maternal age. This is mainly the result of increased meiotic errors, but factors such as differences in abortion rate may play a role as well.
The extra chromosome 21 leads to the physical features and developmental challenges that can occur among people with Down syndrome. Researchers know that Down syndrome is caused by an extra chromosome, but no one knows for sure why Down syndrome occurs or how many different factors play a role.
However, with appropriate medical care most children and adults with Down syndrome can lead healthy lives. The average life expectancy of individuals with Down syndrome is 60 years, with many living into their sixties and seventies.
1. Today the average lifespan of a person with Down syndrome is approximately 60 years. As recently as 1983, the average lifespan of a person with Down syndrome was 25 years. The dramatic increase to 60 years is largely due to the end of the inhumane practice of institutionalizing people with Down syndrome.
Down syndrome, which arises from a chromosome defect, is likely to have a direct link with the increase in stress levels seen in couples during the time of conception, say Surekha Ramachandran, founder of Down Syndrome Federation of India, who has been studying about the same ever since her daughter was diagnosed with ...
An adequate intake of folic acid during pregnancy, believed to protect against neural tube defects (NTDs) in babies, may also help prevent Down's syndrome, researchers report in The Lancet this week.
The only way to avoid Down syndrome at the time of conception is IVF. Pre-screening during IVF can test the embryo in the lab for Down syndrome before the embryo is transferred to the mother. Down syndrome screening is offered to everyone during pregnancy.
Down's syndrome can be traced through families in less than 1% of people with the condition. These people all have rare types of translocation. It is very unusual for parents to have more than one child with Down's syndrome, or for relatives of these parents to have a child with the condition.