What are the methods of prenatal diagnosis? There are two groups: invasive and non-invasive techniques:
- Non-invasive methods:
- examination of the uterus from outside the body (see Leopold’s Maneuvers)
- ultrasound technique (like the 4D ultrasound)
- AFP screening
- Detection of fetal blood cells that have made their way into the mother’s bloodstream, so we can obtain a sample of the baby’s DNA.
- Invasive methods:
Obviously, the aim is to develop a method which is
- safe (some invasive tests pose a risk to the pregnancy)
- sensitive (ultrasound detection may suffer from a high rate of false negatives and false positives)
- cheap (you know our modern world very well)
According to the BBC article, now, scientists are trying to create a non-invase blood test by examining samples of foetal DNA present in the mother’s blood for variations in the sequence of the genetic material. These variations are known as single nucleotide polymorphisms (SNPs).
The Ravgen team, led by Ravinder Dhallan, has been able to maximise the amount of DNA that can be recovered by treating the blood samples with a chemical called formaldehyde.
Ravinder Dhallan, a doctor and researcher, founded Ravgen (Rapid analysis of variations in a genome) in 2000 with the goal of solving major clinical problems. The key to early diagnosis and improved treatment lies in separating relevant, disease-associated genetic signals from the background of non disease-associated signals.
What could be the benefits of that new method according to Alexandra Benachi and Jean-Marc Costa (the Lancet)?
- Being able to identify genetic abnormalities at an early stage not only gives parents the chance to decide whether or not to proceed with the pregnancy, but also alerts medical staff to the need for close monitoring right through to birth.
- They were also able to determine whether the foetus was carrying extra copies of key chromosomes which cause genetic disease such as Down syndrome or Klinefelter syndrome.
- An accurate non-invasive test would mean a lot women with normal babies would not have to be put through a procedure like amniocentesis.
Although, if I want to be neutral, I should list the other side’s concerns:
- The amount of free foetal DNA in maternal blood is low, and although the use of formaldehyde allows an increased amount to be isolated from maternal blood, yields are irregular.
- Only eight women have been assessed in the first trimester – further testing in this stage of pregnancy will be essential.
Thank you Darmok for the suggestions!
Let’s start with the most interesting one:
A Gap Ad Celebrity Speaks to a Geneticist
Specialists of the V.A. Engelgardt Institute of Molecular Biology, Russian Academy of Sciences, and the “Vector” Main Research Center of Virology and Biotechnology created and tested on the cell culture three genetic structures capable to suppress reproduction of human immunodeficiency virus (HIV-1) in human cells.
Researchers in the United States have found that many babies who were delivered vaginally, experience bleeding in and around the brain shortly after birth.
Well, we’ve gone and done yet another study that illustrates we don’t know what to do with the information we get from MRIs when we look at them in newborns and neonates.
Here are the best baby, pregnancy related articles, findings from the last 24 hours :
Children whose mothers were stressed out during pregnancy are vulnerable to mental and behavioural problems like ADHD, mounting evidence suggests… We should be screening women in pregnancy for stress and intervening. It has big public health implications. About a million children in the UK have neurodevelopmental problems – ADHD, cognitive delay, anxiety and so on. About 15% of this might be due to antenatal stress.
A new study finds that women who take folic acid supplements early in their pregnancy can substantially reduce their baby’s chances of being born with a facial cleft… The researchers estimated that 22 percent of isolated CLP cases in Norway could be averted if all pregnant women took 0.4 mg of folic acid per day.
In the wake of a new record for becoming the world’s oldest mother, fertility experts are encouraged by recent research showing that older moms are as capable of good parenting as younger women — but are increasingly concerned about women naively postponing pregnancy till later in life.
A brand new article has been published on U.S. statistics of birth defects. Here is the list of the most common defects:
- heart and circulatory conditions accounted for a third of the 139,100 hospital admissions for birth defects in 2004 (about 33 percent of all birth defect cases)
- gastrointestinal defects accounted for nearly 29,000 admissions (about 19 percent)
- genitourinary birth defects (9 percent)
- nervous system birth defects (5 percent)
- others such as cleft palate, hip deformity, sunken chest, skull and facial bone defects, spinal deformity, and foot deformities (34 percent)
The Medical News Today article says:
Between 1997 and 2004, hospital rates increased by over 25 percent for heart and circulatory birth defects and digestive birth defects. Hospitals spent $2.6 billion treating birth defects. Half the cost was for heart and circulatory congenital problems.
So I should learn much more cardiology. I must add that many diseases may not be discovered or treated until adulthood so this article is just about defects recognized in the first year of life.
If you want to read more on the subject, take a look at the National Statistics For 18 Major Birth Defects, a more detailed perinatal statistics page or the birth defects image category at Wikimedia Commons.
A healthy baby at Wikimedia Commons
The future of prenatal screening belongs to the 4D scan. It uses the same frequency of sound waves as a normal ultrasound, but the sound waves are directed from many more angles, producing a ‘real-time’ video of the foetus.
London-based obstetrician Professor Stuart Campbell, who is the pioneer of 4D scans in Britain, performed the scans for a National Geographic documentary.
He says: ‘It was fascinating to see the babies in more detail than ever before. I was amazed at the detail in the faces – smiles, blinking – and the interaction between multiple foetuses.’
See many more images and video clips here, or the timeline of fetal growth on the GE Healthcare page.
A new blogterview on the subject is coming soon…
Fantastic four: A silicone model of a quadruplet pregnancy (Courtesy of dailymail.co.uk)
Their own placenta and amniotic sac prevent them from touching each other. (Courtesy of dailymail.co.uk)
So good to read something like that. I’m always talking about newborn screening and prevention. I hope to see many more improvements just like this one:
Jaylen Jeremiah Jenkins is a New Year’s baby, and one the first in the state of Georgia to be screened for 28 disorders instead of only 12… And although born a few weeks early, he seems to be a happy and healthy boy. The cost for these new tests is now $40 and is covered by insurance.
The Georgia Newborn Screening Program is now over two decades old. From January 1, 2007, every live born infant must have an adequate blood test for 28 disorders (the most common disorders in the first line, the rarer ones in the other lines):
- Phenylketonuria, Congenital Hypothyroidism, Maple Syrup Urine Disease, Galactosemia, Tyrosinemia, Homocystinuria, Congenital Adrenal Hyperplasia, Biotinidase Deficiency, Sickle Cell Disorders (SS, SC, S-beta thalassemia), Cystic Fibrosis
- Medium-Chain Acyl-CoA Dehydrogenase Deficiency, Isovaleric acidemia, Glutaric acidemia type I, 3-OH 3-CH3 glutaric aciduria (HMG), Multiple carboxylase deficiency, Methylmalonic acidemia, 3-Methylcrotonyl-CoA carboxylase deficiency (3MCC), Propionic acidemia, Beta-ketothiolase deficiency, Very long-chain acyl-CoA dehydrogenase deficiency (VLCAD), Long-chain L-3-OH acyl CoA dehydrogenase deficiency (LCHAD), Trifunctional protein deficiency, Carnitine uptake defect, Citrullinemia, Argininosuccinic acidemia.
Now, we can see how to improve our system. A really great effort from the state of Georgia.