Skip to main content

New story in Health from Time: Genetic Mutations In Father’s Sperm Can Predict Children’s Autism Risk



There’s no question that autism can be traced to a combination of genetic and environmental factors. One genetic contributor in particular has in recent years intrigued scientists studying autism: DNA mutations originating in fathers’ sperm.

Studies have linked autism risk to de novo mutations, or changes in DNA that arise spontaneously in sperm as the germline cell develops, or in the embryo after fertilization. Researchers estimate that such mutations might be involved in anywhere from 10% to 30% of autism cases, and that the older a father is at the time of conception, the higher the chance his sperm will result in de novo mutations that can contribute to autism spectrum disorder. In fact, with every decade of life, the number of de novo mutations in sperm doubles.

In a new study published in Nature Medicine, researchers led by a team at the University of California, San Diego (UCSD) set out to determine if they could match specific disease-causing genetic mutations in the DNA of children with autism to the same mutations in their fathers’ sperm.

The team analyzed DNA from eight sets of fathers and children. In the children, they looked for a phenomenon called mosaicism, which are genetic differences even among cells from the same person. Each time a cell divides, the process can generate mutations, or genetic mistakes—some can be harmful (for example, some can lead to cancer), but most are not because they occur outside of important genes in what are known as “DNA deserts.”

The researchers then matched these changes found in the children to those found in their fathers’ sperm. That confirmed that the de novo mutations were indeed playing some role in contributing to autism.

The researchers also determined what percentage of sperm produced by the father contained these de novo mutations. This knowledge, say the study authors, could potentially lead to a test that can help fathers of children with autism to know how likely they are to have another child affected by the condition. Eventually, the genetic test could also tell parents-to-be if they are at increased risk of having a child with autism. The DNA sequencing technology used is basically the same as used for whole genome sequencing, and the price for that continues to drop, so this wouldn’t be an especially expensive tool.

Currently around 165 genetic mutations have been linked to autism, and conducting a deep analysis of a potential father’s sperm for some of these aberrations could let him know if he is at higher or lower risk of fathering a child who might be affected by autism. (The list of implicated genes continues to grow at a rapid pace, and at the time of the study, the scientists worked with a smaller number of culprit genetic variants). In some of the eight fathers in the study, up to 10% of their sperm carried mutations; if these men decided to have more children, they would have the option of choosing whether they wanted to take measures to reduce the risk their children would be affected. Some, for example, might use IVF so they could screen their embryos for the mutations.

“The point of this is not to eradicate autism,” says Jonathan Sebat, director of the Beyster Institute for Psychiatric Genomics at UCSD, and one of the authors of the new paper. “That is not the goal of this; that is not the point. The point is to inform parents of their risk so they can make their own decisions based on that knowledge.”

The next step is to better understand how de novo mutations function over time. Joseph Gleeson, professor of neuroscience at UCSD and Rady Children’ Institutes for Genomic Medicine and senior author of the paper, says that he and his team have launched another study to explore just that. They recruited male students and faculty from UCSD of varying ages and are sequencing their sperm at different periods of time to track the stability of the mutations.

This line of research could eventually make deep genetic sequencing of sperm commonplace in the family-planning process. Not only could it help parents-to-be make better-informed decisions about their future children’s risk for not only autism, but other conditions believed to be connected to de novo mutations as well, like schizophrenia, epilepsy, and neurodegenerative diseases.

Labels:

Popular posts from this blog

New story in Health from Time: COVID-19 Has Been ‘Apocalyptic’ for Public Transit. Will Congress Offer More Help?

While trying to get to work over the past few months, Brittany Williams, a Seattle home care worker, has often been passed by two or three buses before one stops to let her board. Buses in her area that once carried anywhere from about 50 to 100 passengers have been limited to between 12 and 18 to prevent overcrowding in response to coronavirus, and Williams’ commute, typically a half-hour ride, now takes more than double that time. Other Seattle transit riders have described budgeting as much as an extra hour per trip to account for the reduced capacity, eating into their time at work, school or with family. Even with the ridership limits in place, Williams, 34, doesn’t feel safe on public transit. Some passengers don’t wear face coverings, and bus drivers sometimes ignore capacity limits, she says. On one ride with her seven-year-old son, she decided to get off at a stop far from her home after a driver allowed a crowd of people to board. “It’s very trying. I’ll put...
Read more

New story in Health from Time: A Montana Care Home Refused Free COVID-19 Tests. Now, Nearly Every Resident Has Coronavirus

(BILLINGS, Mont.) — It was meant to be a last line of defense to protect the most vulnerable as the coronavirus spread across the United States : Montana officials offered free testing in May for staff and residents at assisted living and long-term care facilities. But not all of them followed through, according to state data, including a facility in Billings, Montana’s largest city, that cares for people with dementia and other memory problems. The virus has infected almost every resident and killed eight, accounting for almost a quarter of Montana’s 34 confirmed deaths. Thirty-six employees also have tested positive at the facility where 59 people lived before the deaths began. Read more: ‘It’s Getting Worse.’ Nursing Home Workers Confront Risks in Facilities Devastated by Coronavirus While Montana’s rates of confirmed infections and deaths are much lower than other parts of the country, the outbreak at Canyon Creek Memory Care illustrates that even the most simple an...
Read more

New story in Health from Time: An At-Home Coronavirus Test May Be On the Way in the U.S.

As cases of COVID-19 continue to climb in the U.S. , there’s a new urgency to make sure there are as many tests as possible to diagnose people who have symptoms that might indicate an infection. Knowing if people are positive is important for guiding their next steps: self-isolation, avoiding contact with others, and, if their symptoms get worse, seeking medical care. To date, access to tests has been spotty at best across the country, and while more kits are now available than even a week ago , most are gene-based assays that take several days for commercial labs to process and produce results. That may change in about two months if the Food and Drug Administration (FDA) gives Emergency Use Authorization to the first blood-based COVID-19 test in the U.S. Scanwell Health, an at-home test company based in California, licensed the rights to a test developed by Chinese company Innovita, which was used extensively at the height of country’s epidemic earlier this year. “The ...
Read more