Down Syndrome in the Middle Ages

Jan. 30, 2015

By Medical Discovery News

Down syndrome is likely as old as humans themselves, but a recently discovered skeleton of a girl who died 1,500 years ago in France is the oldest confirmed case. The way she was buried seems to indicate that she was not scorned during her life and death in the Early Middle Ages.

Down syndrome, also called Trisomy 21, arises when a person is born with three rather than two copies of chromosome 21. It occurs in one out of 691 babies born in the U.S., making it the most common genetic disorder. Every person with Down syndrome is unique and has different levels of physical and intellectual abilities. The most common physical signs are upward slanting eyes, flattened facial features, ears that are small or unusually shaped, broad hands with short fingers, and a small head.

Other, more serious complications can include poor muscle tone, heart problems, problems swallowing, blockages in the intestines, cataracts or crossed eyes, hearing loss, increased susceptibility to infections, a less-active thyroid gland, and a higher risk of developing leukemia. People with Down syndrome develop dementia at a younger age than the general population. Their intelligence ranges, but with therapies, many Down syndrome children grow up to have jobs and live independently.

The chance of giving birth to a baby with Down Syndrome increases with the mother’s age, from 1 in 1,000 at age 30 to 1 in 100 at age 40. The American College of Obstetrics and Gynecology now recommends that all pregnant women be offered a prenatal screening test for Down syndrome, which is 99 percent accurate.

For centuries, people with Down syndrome have been part of art and literature. It wasn’t until the late 1800s that an English physician named John Langdon Down published the first accurate description, calling the condition “Mongolism.” The modern term Down syndrome became the accepted term in the early 1970s. The cause of Down syndrome, Trisomy 21, was discovered by French pediatrician and geneticist Jerome Lejeune, although Marthe Gautier, a retired pediatric cardiologist and scientist from Paris, now claims she did most of the experimental work that led to the discovery of Trisomy 21.

This newly discovered skeleton, which is the oldest case of Down syndrome found thus far, was unearthed near a church in a fifth- and sixth-century necropolis in Saône-et-Loire in eastern France. The five- to seven-year-old girl exhibited a short, broad skull, flattened skull base, and thin cranial bones, all features of Down syndrome. She was buried on her back with her head in a westerly direction, similar to the 94 others buried there. The archeologists believe that since she wasn’t treated any differently in death, it’s unlikely she was stigmatized when she was alive. But researchers must uncover further details about Down syndrome in the Middle Ages to know more about how she may have lived.

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A Risk-Free Test for Down’s

April 18, 2014

By Medical Discovery News

Keep Calm, It's Only An Extra Chromosome

When it comes to chromosomes, extra copies are not a good thing. Every cell in the human body carries the same genetic information in two copies of 23 chromosomes. Having an extra copy of a chromosome is called trisomy, and an extra copy of chromosome number 21 is what causes Down syndrome.

Physical signs of Down syndrome include upward slanting of the eyes, flattened facial features, small and unusually shaped ears, small heads, and broad hands with short fingers. Down syndrome can also cause more serious conditions such as varying degrees of mental retardation, poor muscle tone, an increased risk of early onset dementia, and heart, stomach, and eye problems. No two cases of Down syndrome are the same, and with therapy and support people with Down syndrome can live long, productive lives.

The risk of Down syndrome increases with the mother’s age during pregnancy. The risk of having a baby with Down syndrome increases from one in 1,300 to one in 25 at ages 25 to 49.

Women who are pregnant with a child who might have Down syndrome typically undergo an ultrasound test and blood tests for markers such as pregnancy-associated plasma protein-A and a hormone known as human chorionic gonadotropin. Abnormal levels of these markers may indicate a problem with the baby. These tests are generally done during weeks 11-13 of pregnancy. The American College of Obstetrics and Gynecology now recommends that all women undergo prenatal testing for chromosomal abnormalities.

Until recently, Down syndrome could only be confirmed by invasive tests that collect cells from the amniotic fluid surrounding the fetus, the placenta, or the fetus itself. These tests can be risky, with a one percent chance of miscarriage. However, a new, noninvasive screening test called circulating cell-free fetal DNA analysis may reduce the need for invasive prenatal tests. Circulating cell-free DNA from the fetus makes up three to 13 percent of the DNA fragments circulating in the mother’s bloodstream during pregnancy.

First, DNA is isolated from the mother’s plasma, the liquid component of blood. Then, there are two ways to determine if there are any chromosomal abnormalities. Massive parallel DNA genomic sequencing can be used to quantify millions of DNA fragments in just a few days and can accurately detect trisomies. Another approach is called Digital Analysis of Selected Regions, which analyzes only the chromosomes in question to evaluate them for any abnormalities.    

These tests are 99 percent accurate, can be done as early as the 10th week of pregnancy, and are more reliable. They can also diagnose other trisomies, like the ones that affect chromosome 18 (Edwards syndrome) and chromosome 13 (Patau syndrome). At this stage, invasive testing is still required to confirm the diagnosis of a trisomy. But in the near future this new technology will reduce or eliminate the need for additional invasive tests that put the fetus at risk. This is only the beginning of the development of safer and more accurate genetic tests.

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