If one identical twin has autism spectrum disorder (ASD), the other twin has a 76 percent chance of also being diagnosed with it. The numbers are lower for fraternal twins. The percentage of fraternal twins who each share an ASD diagnosis is 34 percent for same-sex twins and 18 percent for boy-girl pairs, Dr.
Studies in identical twins have shown that autism has a strong genetic basis: If one identical twin has autism, the other one has it, too, as much as 90 percent of the time. The new work supports these estimates: In 64 of the 78 twin pairs, both twins have an autism diagnosis.
Having older parents, a difficult birth, or infections during pregnancy are all examples of factors that might increase the risk for having ASD. Beyond these factors, certain people are at higher risk than others. For example, ASD is four times more common in males than females.
Studies also show that twins are more likely to suffer from specific health disorders. While they represent just 2 percent of the general population, twins make up 7.4 percent of the nation's cerebral palsy sufferers.
Children who have an older sister with autism are more likely to also have the condition than are those who have an older brother on the spectrum. The risk is higher among younger brothers than younger sisters.
Due to its lower prevalence in females, autism was always thought to have a maternal inheritance component. However, research also suggests that the rarer variants associated with autism are mostly inherited from the father. Ultimately, autism is a complex condition with 100s of genes involved.
The earlier study found that fraternal twins, who shared the same environment before birth but have different DNA, were more likely to both have an autism spectrum disorder (ASD) than siblings who weren't twins.
Anemia is more than twice as common in multiple pregnancies as in a single birth. Multiple birth babies have about twice the risk of congenital (present at birth) abnormalities including neural tube defects (such as spina bifida), gastrointestinal, and heart abnormalities.
It was found that 12.5% of twins had learning disabilities. The most common neurodevelopmental dysfunction were language disorders, poor graphomotor fluency and poor fine motor dexterity.
There are many different factors that have been identified that may make a child more likely to have ASD, including environmental, biologic, and genetic factors.
Advances in diagnostic capabilities and greater understanding and awareness of autism spectrum disorder seem to be largely driving the increase, the Rutgers researchers said. But there's probably more to the story: Genetic factors, and perhaps some environmental ones, too, might also be contributing to the trend.
Parents who have a child with ASD have a 2 to 18 percent chance of having a second child who is also affected. Studies have shown that among identical twins, if one child has autism, the other will be affected about 36 to 95 percent of the time.
The Lyman Twins: Incredible memory
Flo and Kay Lyman are 50-something identical twin sisters with identical autism diagnoses—and the identical ability to remember almost everything. They can tell you the day of the week for any date, past or future (this is known as “calendrical savantism“).
Inheritance. ASD has a tendency to run in families, but the inheritance pattern is usually unknown. People with gene changes associated with ASD generally inherit an increased risk of developing the condition, rather than the condition itself.
The hardest thing about having twins is...
“Managing the movement of two babies. Carrying them both up and down the stairs, getting them into the car, etc.” —Simeon R. “Often having to make one baby wait!” —Catharine D. “Being outnumbered—the logistics of two on one is definitely the hardest.
1. At three months: The three-month stage marks the end of the “fourth trimester” and your twins can better adapt to life outside the womb. For one thing, they'll sleep in longer stretches of about three- to four-hour chunks.
What are the benefits for the twins? Their buddy is always there. They've known each other since they can remember and that is very comforting. They are also a little more social than the average child since they are used to being with another kid since the beginning.
The incidence of handicap was 3.7% in twins, 8.7% in triplets, 11.1% in quadruplets, and 10.0% in quintuplets. The risk of producing at least 1 handicapped child was approximately 1 in 13 pairs of twins (7.4%), 1 in 4 or 5 sets of triplets (21.6%), and 1 in 2 sets of quadruplet and quintuplets (50%).
Twins are at increased risk of fetal and infant death compared with singleton births. 1-3 The increased risk is partly the result of the lower birthweight and gestational age at delivery of multiple pregnancies. At particular risk are monozygotic twins who have poorer survival rates than dizygotic twins.
Monoamniotic-monochorionic Twins
This is the rarest type of twin, and it means a riskier pregnancy as the babies can get tangled in their own umbilical cords. If you have monoamniotic-monochorionic twins, your healthcare provider will monitor your pregnancy closely.
The risk of a firstborn with an autism spectrum disorder triples after a mother turns 35 and a father reaches 40. Although the study was not designed to uncover the cause of the disorder, the findings suggest avenues of research to explore, including the role of environmental toxins.
Perhaps in multiplex families, autism is the result of small genetic changes passed down from one or both parents, scientist theorize. In families with no history of autism, it's possible that autism may arise from a significant genetic change that occurred for the first time in the child with ASD.
Autism is more common in boys than girls. Research from 2021 found that autism is about 4.2 times more prevalent in boys than girls. This means that for every girl with autism, there are 4 boys with autism.