DIAGNOSING DOWN SYNDROME USING BLOOD TEST?

Dr. Mary Norton at the University of California San Francisco (UCSF) has made a recent breakthrough in the research of detecting down syndrome via using the patient's blood to analyze for any abnormalities. Down syndrome is a genetic disorder which plagues 1 out of 700 women. It is caused by having abnormal cell division in chromosome 21. The side effects of Down syndrome vary, including but not limited to learning disabilities and health problems. 

Dr. Norton's team over at UCSF utilized 18,995 pregnant women in their study, having 24% being high-risk, over 35 years of age, while the other 76% were low risk, under 35 years of age. After all that was said was done, it turned out that out off all the women tested 38 were diagnosed with children that had down syndrome. The cfDNA test which incorporated the blood work had a sensitivity rate of 100%, making it the ideal technique in identifying down syndrome.   

New More Accurate Down's Syndrome Test

A new DNA test proves to be more effective at detecting Down’s Syndrome in unborn children than previously practiced methods. This test looks for fetal DNA, also called cell-free DNA, in the mother’s blood stream which is an indicator of Down’s syndrome. Previous tests tested the mothers blood for four different pregnancy related hormones (alpha fetoprotein, estriol, HCG and inhibin A) in the second trimester that may indicate Down’s Syndrome in the fetus. In a new study recently released in the New England Journal of Medicine this method was tested on over 15,000 women pregnant with a single child. The average age was 31. One-fourth of the women were over the age of 35 which is typically considered high risk. It accurately detected the disorder in 38 out of 38 pregnancies with very few false positives.

Down's syndrome is caused by trisomy of chromosome 21. This extra chromosome causes physical and mental changes in the individual. Major characteristics are low muscle tone, stunted growth, an upward slant to the eyes, flattened nose, as well as mental deficiencies that leave an average adult with an IQ of 50 and increased risk of epileptic seizures. 

Being aware of a child’s disorders before they are born will help the child and family adjust. However, could a positive test cause a mother to terminate her pregnancy? I would have to say that would be a consideration for many mothers in such a position. Any genetic test done on a fetus raises this question. There is powering in knowing this information but many parents may find themselves too scared to raise a child with a handicap.

National Down's Syndrome Society

New Drugs May Transform Downs Sydrome

     The article from Scientific America talks about how geneticist, Roger Reeves and his team from Johns Hopkins University have conducted research that may lead towards pharmacological treatments for Down syndrome. Down syndrome is a genetic condition that is caused by an extra copy of chromosome 21 and the over expression of several genes on that chromosome which cause developmental delay leading to impaired learning, memory, and motor skills. Another characteristic of Down syndrome is that the cerebellum is is found to be 40% and is responsible for motor functions, motor learning, and balance.
     Down syndrome was initially thought to be incurable until Reeves and his team began experimenting on mice. They injected the mice with a chemical that stimulates an important neurodevelopmental pathway which stimulates cerebellum growth. Once doing this they found that they had not only "fixed" the cerebellum in mice but three months later they were able to complete a water maze. Such a task would usually thought to be predominantly controlled by the hippocampus so the researchers are still unsure whether they "inadvertently repaired" the hippocampus or if the cerebellum is actually responsible for more than what has been previously thought. 
     This type of treatment given to humans is thought to allow those with Down syndrome to live more independent lives. I think that these results are very exciting not only from a genetics standpoint and those who are affected by Downs but from the viewpoint that there is a hope of finding "cures" or treatments for other similar disabilities. Despite the excitement, I think we also need to consider being cautious in our evaluations of this research because sometimes research from animals fail to translate over to humans.

Article Link: http://www.scientificamerican.com/article/new-drugs-may-transform-downs-syndrome/

Info on Down syndrome: http://www.ndss.org/Down-Syndrome/What-Is-Down-Syndrome/

Trisomy 21 Linked to Brain Protein Loss

From an article from BBC News Health, researchers have found that trisomy 21, commonly known as Down’s syndrome, has been found to cause protein loss in the brain, specifically the SNX27 protein. The SNX27 protein is what activates some glutamate receptors in the brain and is important for brain function according to the research found in Nature Medicine. In the study, the researchers reinstated the protein in mice affected with Down’s and found that their cognitive abilities increased. After this finding, the researchers studied the brains of humans with Down’s and found the same lack of the SNX27 protein. This seems to be a very hopeful study to get further insight into the condition known as Down’s syndrome and may one day be able to improve cognitive function in people affected. Still, much more research seems needed to be done in order to figure out a safe way to restore this protein level in humans, if there is one. Also, the has been no human tests to date, so no one knows exactly how it could react in humans. While this study has found a very important effect of trisomy 21, much more research will need to be done to figure out whether or not a treatment to restore this protein in humans is feasible and safe.

Too Old to Be a Dad?

Studies in Nature magazine are linking Down's syndrome, schizophrenia, autism, to babies who have older fathers. In an article in the American Journal of Men’s Health babies with older fathers are more likely to have certain cancers, cleft lip, and low and premature births. When a man and women are around there 20s they pass about 20 novo defects but when the man is 65 the number has doubled to 40s while the women remain the same.

There not only medical concerns they are also social concerns. “Even if you’re Paul McCartney’s child, you get ripped off if your father dies when you’re in your early 20s,” says Julianne Zweifel, a clinical professor of obstetrics and gynecology at the University of Wisconsin.
Older fatherhood isn’t all bad: testosterone rates drop about 1% per year as men age, making them less reactive and more patient, and a professionally established middle-aged man is likely to have more time and money to devote to his kids than a twenty-something who’s just getting started. My parents had me later in life but I think they made wiser decisions because of it.

http://healthland.time.com/2013/04/11/too-old-to-be-a-dad/

The Heart of Down Syndrome

In a recent article, researchers from the Sanford-Burnham Medical Research Institute and the University of Utah have reported a new study to identify two genes which are known to be responsible for heart defects in people who have down syndrome.  This study was tested by using both fruit flies and mice, which both had these two genes present, which produced much thicker ventricle walls. These two genes are known to work together to interfere with the development of their heart as well as thier heart function.  Although down syndrome has has the most common rate of heart conditions, this disorder effects one in seven hundred births. If there is any possible way to somehow use this new study to find cures to these horrible heart defects, this could help and save lives of many down syndrome patients

Cancer Treatment and Down's Syndrome: The "Extra" Link

A large number of cancers are uncommon in individuals with Down’s syndrome. With less than 10 percent of cancer mortalities, it has become an attention-grabbing topic for scientists in the recent years.  Research done by Kwan-Hyuck Baek, Sandra Ryeom, et al. has stated that Down’s syndrome candidate region-1 (DSCR1) is an angiogenesis suppressor located in chromosome 21. Angiogenesis is the process of which new capillary blood vessels grow from existing vessels in the body, and when there is an imbalance in vascular endothelial growth factor (VEGF), a protein that stimulates angiogenesis, it could lead to over growth and cancer. Since individuals with Down’s syndrome have an extra set of chromosome 21, it was hypothesized that they also have an extra copy of the DSCR1 gene.  Further studies have shown that chromosome 21 does indeed have genes that contribute to angiogenesis suppression; therefore, individuals with Down’s syndrome have an extra set of these genes. In this study, mice were bred with three copies of the DSCR1 gene and then injected with cancer cells. The mice in the study developed tumors roughly 50 percent slower than the mice without the extra gene. This research is imperative to the medical field because it holds the key to ultimately suppressing VEGF in cancer patients without Down’s syndrome.