Down syndromeoccurs when a baby develops an extra copy of the 21st chromosome during pregnancy, resulting in telltale symptoms. These distinctivesigns and symptoms除了发展和智力困难外，还可以包括可识别的面部特征。
有兴趣了解更多吗？我们在下面汇编了有关唐氏综合症的一些事实和统计数据。
Each year, about 6,000 babies are born with Down syndrome in the United States
The estimated incidence of Down syndrome is between 1 in 1,000 to 1 in 1,100 live births worldwide, according to the
Down syndrome is the most common chromosomal disorder in the United States
Though Down syndrome is the most commonly occurring genetic chromosomal disorder, the way the condition presents itself in each person will differ.
Some people will have mild to moderate intellectual and developmental problems, while others might have more severe complications.
健康也是如此，有些患有唐氏综合症的人可能很健康，而另一些人可能患有各种与健康有关的并发症，例如心脏缺陷。
存在三种不同类型的唐氏综合症
While the condition may be thought of as a singular syndrome, there are actually three different types.
Trisomy 21, or nondisjunction, is the most common. It accounts for
The other two types are called易位andmosaicism. Regardless of which type a person has, everyone with Down syndrome has an extra pair of chromosome 21.
Babies of every race can have Down syndrome
Down syndrome does not occur in one race more than another.
In the United States, however, black or African American infants with Down syndrome have
People with Down syndrome have an extra chromosome
The nucleus of a typical cell contains 23 pairs of chromosomes, or 46 total chromosomes. Each of these chromosomes determines something about you, from your hair color to your sex.
People with Down syndrome have an extra copy or partial copy of chromosome 21.
Maternal age is the only certain risk factor for Down syndrome
Eighty percentof children with either trisomy 21 or mosaicism Down syndrome are born to mothers who are younger than 35 years old. Younger women have babies more frequently, so the number of babies with Down syndrome are higher in that group.
However, moms who are older than 35 are more likely to have a baby affected by the condition.
According to theNational Down Syndrome Society, a 35-year-old woman has approximately a 1 in 350 chance of conceiving a child with Down syndrome. This chance increases gradually to 1 in 100 by age 40 and approximately 1 in 30 by age 45.
唐氏综合症是一种遗传疾病，但不是遗传
Neither trisomy 21 nor mosaicism is inherited from a parent. These cases of Down syndrome are the result of a random cell division event during the baby’s development.
But三分之一of translocation cases are hereditary, accounting for about 1 percent of all cases of Down syndrome. That means the genetic material that can lead to Down syndrome is passed from parent to child.
Both parents can be carriers of the translocation Down syndrome genes without showing any signs or symptoms of Down syndrome.
Women who have had one child with Down syndrome have an increased chance of having another child with the condition
If a woman has one child with the condition, her risk for having a second child with the syndrome is about1 in 100直到40岁。
The risk of having a second child with the translocation type of Down syndrome is about 10 to 15 percent if the mother carries the genes. If the father is the carrier, however, the risk is about 3 percent.
People with Down syndrome can have a variety of complications
Infants with Down syndrome who also had a congenital heart defect were found to be
Likewise, acongenital heart defect是20岁之前死亡的最大预测因素之一。但是，心脏手术的新发展正在帮助患有这种病情更长的人。
Compared to children without Down syndrome, children with Down syndrome are at higher risk for complications that include hearing loss —
Symptoms of Down syndrome aren’t the same for each person
Down syndrome causes many distinct characteristics, like:
- a small stature
- upwardly slanting eyes
- a flattened bridge of the nose
- a short neck
However, each person will have different degrees of the characteristics, and some of the features may not appear at all.
People with Down syndrome can work but often have jobs that underutilize their skills
According toone national survey in 2015,只有57%的成年人患有唐氏综合症的回答e employed, and only 3 percent were full-time paid employees.
More than 25 percent of respondents were volunteers, almost 3 percent were self-employed, and 30 percent were unemployed.
Moreover, the highest percentage of people worked in the restaurant or food industry and in janitorial and cleaning services, even though a large majority of adults reported that they use computers.
在第一个生日之前死亡的唐氏综合症的婴儿人数正在下降<
From 1979 to 2003, the rate of death for a person born with Down syndrome during their first year of life fell by about
That means only about 5 percent of babies born with Down syndrome will die by age 1.
The average age of survival continues to increase
At the turn of the 20th century, children with Down syndrome rarely lived past 9 years old. Now, thanks to advancements in treatment, the majority of people with the condition will live toage 60. Some may live even longer.
Early intervention is vital
While Down syndrome can’t be cured, treatment and teaching life skills can go a long way to improve the child’s — and eventually the adult’s — quality of life.
Treatment programs通常包括身体，言语和职业疗法，生活技能课程和教育机会。许多学校和基金会为患有唐氏综合症的儿童和成人提供高度专业的课程和课程。
Half of older adults with Down syndrome will develop memory loss
People with Down syndrome are living to be much older, but as they age, it’s not uncommon for them to develop thinking and
According to the Down’s Syndrome Association, by their 50s, approximatelyhalfof the people with Down syndrome will be showing evidence of memory loss and other problems — such as loss of skills — associated with havingAlzheimer’s disease.
虽然唐氏综合症仍然是今天在美国出生的最常见的染色体疾病，但未来对他们来说越来越光明。
People with the condition are prospering, and their lifespans are increasing thanks to the improvement of treatments and therapies.
此外，对与该病相关的预防措施和并发症的理解增加，使护理人员，教育者和医生可以预料和计划更长的未来。
Jen Thomas is a journalist and media strategist based in San Francisco. When she’s not dreaming of new places to visit and photograph, she can be found around the Bay Area struggling to wrangle her blind Jack Russell terrier or looking lost because she insists on walking everywhere. Jen is also a competitive Ultimate Frisbee player, a decent rock climber, a lapsed runner, and an aspiring aerial performer.