www射-国产免费一级-欧美福利-亚洲成人福利-成人一区在线观看-亚州成人

您現(xiàn)在的位置: Language Tips> Audio & Video> Special Speed News  
   
 





 
Understanding Down syndrome
[ 2009-09-10 09:17 ]

 

People with the disorder are living longer and more productive lives than in the past. But they may also face a higher risk of Alzheimer’s disease at an early age.

This is the VOA Special English Health Report.

Human genes are normally organized along 46 chromosomes in our cells, 23 from each parent.

Understanding Down syndrome

But some people are born with an extra copy of the 21 chromosome. This third copy is a result of a mistake in cell division. The name for this condition is Down syndrome.

A British doctor named John Langdon Down first described it in the 1860s. An estimated 350 thousand people in the United States have Down syndrome.

Many babies with Down syndrome have low muscle tone, so they need extra support when they are held. Their heads are smaller than average and they can have unusually shaped ears. Also, their eyes often angle upward.

People with Down syndrome often have other conditions. These include problems with their heart and with their breathing and hearing. A lot of these conditions, though, are treatable.

About one in every 100 people with Down syndrome will develop leukemia, a cancer of the blood. But the National Down Syndrome Society says many of these cases are curable as well.

As a result, people with Down syndrome are living longer. In the early 1980s they lived an average of just 25 years. Today the life expectancy for someone with Down syndrome is 60 years.

But with that longer life, people with Down syndrome may have an increased risk for Alzheimer's disease at an early age. An estimated 25 percent of those 35 and older show signs of the brain-wasting disease. It slowly destroys memory, thinking and reasoning skills. Alzheimer's is usually not found in the general population until people are over the age of 65.

Down syndrome is the most common genetic cause of mental retardation. Many people with Down syndrome are mildly to moderately retarded. Many, however, are able to attend regular classes with other students. And later, as adults, many are able to hold jobs and lead independent lives.

There are tests that can be done to look for Down syndrome during pregnancy.

The risk of having a baby with Down syndrome increases with the mother's age. The rate is one in every 1200 births at age 25. At 35 it rises to one in 350 births. And at 45 the rate is one in 30.

And that's the VOA Special English Health Report, written by Caty Weaver. I'm Steve Ember.

chromosome: a circular strand of DNA in bacteria that contains the hereditary information necessary for cell life 染色體

leukemia: a malignancy of blood-producing tissues, characterized by proliferating immature white blood cells and infiltration of the spleen, liver, and other organs 白血病

Related stories:

New study disputes 'depression dene' finding

Deferred Happiness Syndrome

Biomarkers show little help in predicting heart disease

Obese People Have 'Severe Brain Degeneration'

(Source: VOA 英語點(diǎn)津編輯)

 

英語點(diǎn)津版權(quán)說明:凡注明來源為“英語點(diǎn)津:XXX(署名)”的原創(chuàng)作品,除與中國日報網(wǎng)簽署英語點(diǎn)津內(nèi)容授權(quán)協(xié)議的網(wǎng)站外,其他任何網(wǎng)站或單位未經(jīng)允許不得非法盜鏈、轉(zhuǎn)載和使用,違者必究。如需使用,請與010-84883631聯(lián)系;凡本網(wǎng)注明“來源:XXX(非英語點(diǎn)津)”的作品,均轉(zhuǎn)載自其它媒體,目的在于傳播更多信息,其他媒體如需轉(zhuǎn)載,請與稿件來源方聯(lián)系,如產(chǎn)生任何問題與本網(wǎng)無關(guān);本網(wǎng)所發(fā)布的歌曲、電影片段,版權(quán)歸原作者所有,僅供學(xué)習(xí)與研究,如果侵權(quán),請?zhí)峁┌鏅?quán)證明,以便盡快刪除。
相關(guān)文章 Related Story
 
 
 
本頻道最新推薦
 
Rat race 激烈的競爭
聯(lián)合競標(biāo) joint bid
揭秘:米歇爾·奧巴馬如何練就健美雙臂?
磨洋工 warm-chair attrition
Manners 文明禮貌
翻吧推薦
 
論壇熱貼
 
經(jīng)典英語口語,不得不看(推薦)
I chocolate you!怎么翻譯?
請教obama演講里的一句話
 
曬曬小D機(jī)器人暴強(qiáng)的翻譯
美國校園最in俗語大全

 

主站蜘蛛池模板: 男女性高爱潮免费网站 | 大片刺激免费播放视频 | 精品国产区一区二区三区在线观看 | 国产精品国产自线在线观看 | 欧美日韩精品一区二区三区视频在线 | 两性免费视频 | 青青草国产一区二区三区 | 成人免费观看www在线 | 男的操美女 | 男操女视频 | 欧美三级做爰在线 | 亚洲精品高清在线 | 国产精品久久久久久久久 | 美女张开大腿让男人捅 | 韩国美女一级毛片 | 香港av三级 | 国产成年人网站 | 韩国毛片免费 | a级网站在线观看 | 国产精品久久久久久一级毛片 | 人成精品视频三区二区一区 | 清纯偷拍精品视频在线观看 | 99精品在线观看视频 | 国产美女一级特黄毛片 | 窝窝午夜精品一区二区 | 成人毛片在线 | 国产精品亚洲二线在线播放 | 亚洲成人国产 | 在线はじめてのおるすばん | 亚欧毛片 | 亚洲免费成人网 | 中日毛片 | 国产原创视频在线 | 国产综合视频在线观看一区 | 久久99精品久久久久久青青91 | 亚洲综合色吧 | 国产成人18 | 免费国产不卡午夜福在线 | 欧美国产精品不卡在线观看 | 国产三区视频在线观看 | 波多野结衣在线中文 |