Posts Tagged ‘ genetic testing ’

Parents of an Autistic Child Often Decide Not to Have More Kids

Monday, June 23rd, 2014

A new study conducted by University of California researchers has found that parents who have a child diagnosed with an autism spectrum disorder (ASD) often choose not to have more children, citing the energy, expense, and complicated logistics required to care for an autistic child.  More from HealthDay News:

In the study, a team led by Neil Risch of the University of California, San Francisco, looked at nearly 20,000 families in California. All of the families included a child with autism born between 1990 and 2003.

These families were compared to a “control” group of more than 36,000 families that did not have a child with autism.

Parents whose first child had autism were about one-third less likely to have a second child than parents in the control group, the study found, while parents who had a later-born child with autism were equally less likely to have more children.

The researchers also found that parents of children with autism were likely to continue having other children until the child with autism began showing signs of or was diagnosed with the disorder. This suggests that not having more children is a decision made by parents, rather than a reproductive problem, the study authors said.

According to Risch’s team, in calculating the risk to families of having a second child with autism, most prior studies on the issue have ignored the fact that many families with an autistic child may have already made the decision to stop reproducing. That means the real risk of having a second child with autism may be higher than has been generally thought, they noted.

So, in the new study, Risch’s team accounted for the decision by some couples to stop having kids after they had already had a child with autism. When that factor was taken into account, there was about a one in 10 chance that the parents of child with autism who did decide to have more children would have a second child with autism, the investigators found.

The study was published June 18 in the journal JAMA Psychiatry.

“While it has been postulated that parents who have a child with [autism] may be reluctant to have more children, this is first time that anyone has analyzed the question with hard numbers,” Risch, a professor of epidemiology and biostatistics at UCSF, said in a university news release.

He believes that the “findings have important implications for genetic counseling of affected families.”

Study co-author Lisa Croen, an epidemiologist and director of the Autism Research Program at Kaiser Permanente Northern California, noted, “unfortunately, we still don’t know what causes autism, or which specific conditions make it more likely.”

And, she added, “We are hoping that further research will enable us to identify both effective treatment strategies and, ultimately, modifiable causes of the disorder, so parents won’t have to curtail their families for fear of having another affected child.”

Image: Boy at a playground, via Shutterstock

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Blood Test Improving Early Detection of Fetal Abnormalities

Friday, February 28th, 2014

A simple blood test taken early in pregnancy is showing high degrees of accuracy in predicting chromosomal abnormalities in fetuses, a study published in the New England Journal of Medicine has found.  The finding is welcome news to pregnant women who worry about having invasive prenatal screenings, some of which, like amniocentesis, carry a small risk of miscarriage.  More from The New York Times:

The study, published on Wednesday in The New England Journal of Medicine, found that the fetal DNA test was 10 times better in predicting cases of Down syndrome than the standard blood test and ultrasound screening, and five times better in predicting the other disorder, Trisomy 18. It also greatly reduced the number of false-positive results.

It could prevent many women who would otherwise get the standard blood test from needing to confirm positive results with invasive tests like amniocentesis or chorionic villus sampling, which can be stressful, much more costly and carry small risks of miscarriage. “Nine out of 10 women who are currently being referred for further testing would not need invasive tests,” said the lead author of the study, Dr. Diana Bianchi, the executive director of the Mother Infant Research Institute at Tufts Medical Center’s Floating Hospital for Children.

A positive result on the DNA screening would still need to be confirmed with invasive tests, because in more than half the cases in which the newer test predicted a disorder, there was no chromosomal abnormality. But a negative result would provide confidence that these two major chromosomal disorders are absent.

“It’s a better mousetrap, there’s no doubt about that,” said Dr. Michael Greene, director of obstetrics at Massachusetts General Hospital and co-author of an editorial about the study. “If the test is normal, the overwhelming probability is that your fetus is normal. There will be far fewer women who will be encouraged to have invasive testing, and, as a result, far fewer miscarriages.”

The screen analyzes blood from women who are at least 10 weeks pregnant. At that point, about 10 percent of DNA in the blood will be fetal DNA from the placenta, Dr. Bianchi said.

Image: Pregnant woman at the doctor, via Shutterstock

The results of our Ancient Chinese Gender Predictor could spill the beans about whether you’re having a boy or girl.

Should You Have an Amniocentesis?
Should You Have an Amniocentesis?
Should You Have an Amniocentesis?

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Genetic Testing of Embryos Spurs Ethics Debate

Tuesday, February 4th, 2014

The debate over the morality of performing genetic tests on embryos–and deciding not to use those carrying  deadly genetic disorders for potential pregnancies–continues, as a New York Times report explains:

….The procedure also raises unsettling ethical questions that trouble advocates for the disabled and have left some doctors struggling with what they should tell their patients. When are prospective parents justified in discarding embryos? Is it acceptable, for example, for diseases like GSS [Gerstmann-Straussler-Scheinker disease], that develop in adulthood? What if a gene only increases the risk of a disease? And should people be able to use it to pick whether they have a boy or girl? A recent international survey found that 2 percent of more than 27,000 uses of preimplantation diagnosis were made to choose a child’s sex.

In the United States, there are no regulations that limit the method’s use. The Society for Assisted Reproductive Technology, whose members provide preimplantation diagnosis, says it is “ethically justified” to prevent serious adult diseases for which “no safe, effective interventions are available.” The method is “ethically allowed” for conditions “of lesser severity” or for which the gene increases risk but does not guarantee a disease.

There is no question that the method’s use is increasing rapidly, though no group collects comprehensive data, said Dr. Joe Leigh Simpson, vice president for research at the March of Dimes and past president of the American Society for Reproductive Medicine.

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Girls’ Stem Cell Donation May Save Future Lives

Monday, December 9th, 2013

Fifteen-year-old Hayley Mogul and her 9-year-old sister both extremely rare genetic disorders–so rare, that a cure isn’t even being sought by scientists–that has had severe neurological and metabolic consequences for the sisters.  But their participation in cutting edge research that combines stem cell and genetic techniques may give hope to future generations.  NBC News reports:

There’s no cure for their rare disorders, caused by unique genetic mutations. But for once, there’s an advantage to having conditions so rare that drug companies cannot even think of looking for a cure. The sisters are taking part in a whole new kind of experiment in which scientists are literally turning back the clock on their cells.

They’re using an experimental technique to transform the cells into embryonic form, and then growing these baby cells in lab dishes.

The goal is the get the cells to misfire in the lab in just the same way they are in Hayley’s and Bari’s bodies. It’s a new marriage of genetics and stem cell research, and represents one of the most promising applications of so-called pluripotent stem cells.

“One day these two girls will probably change the face of medicine as we know it,” said their father, Steven Mogul.

Steven and Robyn Mogul don’t understand why both their daughters ended up with the rare mutations, which cause a range of neurological and metabolic problems.

“We have been tested,” said Mogul, a 45-year-old wealth manager living in Chicago. “We don’t have any mutations, and there are no developmental issues. We have no idea how it happened. “

The girls need special schooling and physical therapy. They must wear diapers, and when they get a cold or the flu, they can develop dangerously low blood sugar. “When the kids get sick, get colds or flu, we have to get them to the hospital,” Mogul said.

Hayley, 15, has a mutation in a gene called RAI1, which can cause Smith-Magenis syndrome. The syndrome affects 1 in 25,000 people and can disturb sleep patterns, cause obesity and behavioral issues. But Hayley’s mutation is unique and puzzling. Bari, 9, has an RAI1 mutation and a similarly unique mutation in the GRIN2B gene, which can cause learning disabilities.

“Bari doesn’t talk,” Mogul said. “She walks around, she gets around and lets you know what she wants. She is eating baby food and she is drinking from bottles.”

Hayley can attend school and can read, but lacks the fine motor skills needed to write. It’s especially unusual for two children in the same family to end up with such rare, and different, mutations.

Image: DNA, via Shutterstock

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Experimental Blood Test Will Attempt to Detect Autism

Monday, December 10th, 2012

A new blood test is being examined to see whether it can detect genetic markers that can identify autism spectrum disorders (ASD). If successful, the test would greatly improve doctors’ ability to diagnose the disorders–and begin interventions–earlier. More from CNN.com:

“In a study published in the journal PLOS ONE, researchers from Children’s Hospital Boston describe a new experimental test to detect the developmental disorder, based on the differences in gene expression between kids with autism spectrum disorder (ASD) and those without the condition.

The blood-based test appears to predict autism relatively accurately, at least among boys, and has already been licensed to a company, SynapDx, for commercial development. In an e-mail statement to TIME, a spokeswoman for SynapDx said the company plans to start clinical trials of the new test in early 2013.

The new blood test for autism is intriguing, researchers say, because it seems to be at least as effective as any other genetic test for autism that doctors currently use. Scientists believe that autism has some genetic basis, based on genes that have been associated with the disorder, and the fact that the condition seems to run in families.

“A week does not go by where you don’t hear about a genetic mutation that has been linked to autism in at least a few families,” says Isaac Kohane, a pediatric endocrinologist and computer scientist at Children’s Hospital Boston, and the senior study author on the new article in PLOS ONE. Kohane is a scientific adviser for SynapDx, but says he does not own any stock in the company.

But autism is a complex condition, he says, with many possible genetic determinants. And the precise genetic mechanism, or more likely mechanisms, are still poorly understood.”

Image: Blood test tubes, via Shutterstock

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