Resources on the risk for future siblings | Autism PDD

Excellent resource - thanks.

Edit: A 2011 study offers at this point the most reliable numbers:

19% chance if an older sibling has an autism spectrum diagnosis (ASD)

26% chance if the new sibling is a boy

32% chance if two or more older siblings have ASD

It doesn't look like the older siblings' symptom severity or gender affected the risk.

http://pediatrics.aappublications.org/content/early/2011/08/ 11/peds.2010-2825.full.pdf+html

http://abcnews.go.com/Health/Autism/siblings-face-high-recur rence-risk-autism/story?id=14290496

The important thing is to monitor siblings closely and start intervention early.

Below is older information, as originally posted.

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What are your chances of having another child on the spectrum? This question comes up on our forum periodically, so I thought I'd gather information on this in one spot. If anyone else has statistics on this subject, let me know.

2 to 8%, according to an article

cited by the Center for Disease Control.

"The recurrence rate in siblings of affected children is

Source: http://pediatrics.aappublications.org/cgi/content/full/113/5 /e472

The authors base those numbers on the following published work:

Gillberg C, Coleman M. The Biology of the Autistic Syndromes. 3rd ed. London, UK: Mac Keith Press, Distributed by Cambridge University Press; 2000

Chakrabarti S, Fombonne E. Pervasive developmental disorders in preschool children. JAMA. 2001;285 :3093 –3099

Chudley AE, Gutierrez E, Jocelyn LJ, Chodirker BN. Outcomes of genetic evaluation in children with pervasive developmental disorder. J Dev Behav Pediatr. 1998;19 :321 –325

The CDC cited Muhle's article here:

http://0-www.cdc.gov.mill1.sjlibrary.org/ncbddd/autism/overv iew.htm#_ftnref6

10% chance if the family has one autistic child,

50% chance if the family already has two autistic children,

according to an interview with a genetic researcher:

Lisa Jo Rudy of www.autism.about.com was lucky enough to get a personal interview with the Cold Spring Harbor researcher, Jonathan Sebat. Sebat said that the average risk for child number two having autism is 10%, but the risk is lower if it's the result of a spontaneous mutation rather than heredity. If you have two kids with autism, the risk is up to 50% for male third-borns.

Anyhow, anyone interested in reading more can go to:

http://autism.about.com/b/a/257919.htm (Part 1)

http://autism.about.com/od/causesofautism/a/newmutations.htm (Part 2)

28%, if you interpret the results

of an early diagnosis study

I also recently ran across a relevant study by Dr. Landa at Kennedy Krieger. That study investigated very early diagnosis (14 months), but you can also draw conclusions about risks because the study involved baby siblings of autistics.

Thirty of the 107 baby siblings ended up with an autism label, either at 14 months or later at age 3. That is 28% -- which seems significantly higher than 10%. Problem is, we don't know if any of these baby sibs came from families that already had more than one child diagnosed.

You can read Newsweek's report on that study here:

http://www.msnbc.msn.com/id/19588967/site/newsweek/page/0/

Sample topic on our forum:

http://www.autism-pdd.net/forum/forum_posts.asp?TID=19546&am p;am p;am p;KW=Newsweek&PN=0&TPN=1

NorwayMom40770.9771412037Thanks Norway mom!

Autism.about.com has some resources on this topic:

http://autism.about.com/od/medicalissuesandautism/f/genetics faq.htm - "Will our next child be autistic?"

http://autism.about.com/od/copingwithautism/f/secondchild.ht m?nl=1 - "Should parents of a child with autism have more children?", things to consider according to two psychologists, one of whom himself has child with autism.

On another topic, someone wondered if we can predict how mild/severe a future sibling's autism might be, based on how mild/severe the autism is for the other child/children already born to the family.

I tried a google search today, and found a research study that looked for subclinical social impairment in boys whose sibling(s) had autism, PDD-NOS, or a non-autistic "psychopathology" (ie ADHD, anxiety or affective disorder).

The siblings showed social impairment, with the greatest impairment among those who had multiple siblings with autism. Those who had a sibling with PDD-NOS were also socially impaired, more so than those who had a special-needs sibling with ADHD, etc.

They were looking at subclinical social impairment, but if they were looking at autistic impairment, I wonder if they'd find the same results -- greater impairment in those whose sibling(s) had autism vs. those whose sibling had PDD-NOS.

Anyway, here's a link to the article:

http://ajp.psychiatryonline.org/cgi/content/full/163/2/294

Comments on the risk to future siblings from the new Chromosome 16 research:

<quote>

The chromosome 16 deletion/duplication accounts for an estimated 1 percent of autism cases, adding to the roughly 15 percent of cases of autism with known genetic causes, says Miller, who is also a clinical geneticist and a member of the Consortium.

"I don't think we're going to find one cause that explains 50 percent of autism," Miller notes. "It's going to be an incremental process. Even if it's 1 percent at a time, that's still progress. And we'll eventually get to the point where we can figure out what's going on in each particular family, and help them figure out their chances of having another child affected with autism."

In the majority of cases the chromosome 16--deletion occurred de novo, meaning that it was not inherited from a parent, but instead occurred during embryonic development. This information is helpful in counseling families because it suggests that the chances of another child in the family having autism are small, perhaps five percent rather than 50 percent if the trait is inherited from parent, Miller says. "We would need to have more data from more individuals before we could give families an exact number," he adds.

Source: http://www.childrenshospital.org/newsroom/Site1339/mainpageS 1339P1sublevel392.html

Actual study here: http://content.nejm.org/cgi/content/full/NEJMoa075974

In October 2008, Jorg Hager and Geraldine Dawson presented research on genetic testing to determine sibling risk.

Here's an article on it called "Genetic Test May Help Assess Autism Risk in Siblings of Affected Children" but I'm afraid I didn't get much out of it since it wasn't written in plain English.

http://www.medscape.com/viewarticle/582008

Hi!

I am a mommy of a 10 month old and a behavioral therapist working with kiddos with PDD. In my experiences, this topic is so prevelent, and I am glad to see there is so much support out there! I am actually writing my dissertaion on the topic titled: The Decision to Have Another Child: Experiences of Parents of Children with Autism Spectrum Disorder.

So far all of the statistics and links I have seen on this posting are consistent to the reserach I have seen in my literature review.

I am still in the proposal stages of my dissertation, but will start collecting participants and data within the next 6 months (as you all know, it is hard to get anything done while caring for a baby!). If any of you would like to share your experiences with me, I'd greatly appreciate it! My criteria is that you are either pregnant or planning to get pregnant, your child with PDD is your only child, and that you decided to have another child after the diagnosis of PDD was made with your first child. The results form my research will help write a grant to fund a support group I am developing for families in the San Diego area.

Best wishes to all of you in your decision process!

Lisa

Bumping this one. It's always smart to have a low threshhold for getting other children in the family evaluated.

A 2011 study offers at this point the most reliable numbers:

19% chance if an older sibling has an autism spectrum diagnosis (ASD)

26% chance if the new sibling is a boy

32% chance if two or more older siblings have ASD

It doesn't look like the older siblings' symptom severity or gender affected the risk.