Siblings With Autism Share More of Their Fathers Genome Not Their Mothers

Author: Cold Spring Harbor Laboratory
Published: 2023/05/22 - Updated: 2024/06/20
Publication Details: Peer-Reviewed, Research, Study, Analysis
Topic: Autism Information - Publications List

Page Content: Synopsis - Introduction - Main

Synopsis: Research finds that in families that have two or more children with autism spectrum disorder (ASD) the siblings shared more of their father's genome. While the discovery reveals a new potential source of ASD, it also poses a provocative question. Could other disorders play by the same genetic rules?

Defining Genome

Genome

The study of the genome is called genomics. Genomics is the study of all of a person's genes (the genome), including interactions of those genes with each other and with the person's environment. In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It's hard to derive a precise definition of "genome", as it usually refers to the DNA (or sometimes RNA) molecules that carry the genetic information in an organism but sometimes it is difficult to decide which molecules to include in the genome definition.

The Human Genome Project was one of the greatest scientific feats in history. Launched in October 1990 and completed in April 2003, the Human Genome Project generated the first sequence of the human genome thereby providing fundamental information about the human blueprint, which has since accelerated the study of human biology and improved the practice of medicine.

Introduction

"Sharing Parental Genomes by Siblings Concordant or Discordant for Autism" - Cell Genomics.

For decades, Cold Spring Harbor Laboratory scientists and collaborators have invested millions of dollars into deciphering the genetic causes of autism spectrum disorder (ASD). Their efforts have produced useful insights for diagnosticians, therapists, and educators, helping to change the way people think about this common neurodevelopmental disorder. Now, they've taken their work another big step further, once again overturning popular assumptions about autism and its genetic origins.

Focus

Cold Spring Harbor Laboratory (CSHL) researchers have flipped the script on autism spectrum disorder (ASD) genetics. Scientists long thought that siblings born with ASD share more of their mother's genome than their father's. But CSHL Associate Professor Ivan Iossifov and Professor Michael Wigler have now shown that, in many cases, it's dad who might be playing a bigger genetic role.

Autism spectrum disorders cover a range of neurological and developmental conditions. They can affect how a person communicates, socializes, learns, and behaves. ASD may also manifest as repetitive behaviors or restricted interests. In the United States, it affects around one in 36 children.

"There are children diagnosed with autism who are high functioning," Iossifov says. "They have a completely productive life, although they have some minor troubles in social interactions, as most of us do. But also, there are children diagnosed with autism who never learn to speak, and they have definitely a difficult life."

Over the last two decades, CSHL scientists have led a multimillion-dollar effort to uncover the genetic origins of autism. They discovered thousands of genes that, when damaged, may cause a child to be born with ASD. But their work was not able to account for all cases of ASD. So Iossifov and Wigler set out to find the missing sources.

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Diagram depicts autism family tree. — Diagram depicts autism family tree - Image Credit: Cold Spring Harbor Laboratory.

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The duo analyzed the genomes of over 6,000 volunteer families. They found that in families that have two or more children with ASD, the siblings shared more of their father's genome. Meanwhile, in families where only one sibling had ASD, the children shared less of their father's genome. While the discovery reveals a new potential source of ASD, it also poses a provocative question. Could other disorders play by the same genetic rules?

No one is sure how dad's genome makes its mark on children with ASD. But Iossifov has a couple interesting ideas. He thinks some fathers may carry protective mutations that fail to get passed on. Or fathers may pass down mutations that trigger the mother's immune system to attack the developing embryo. Both theories offer hope for parents of children with ASD and other neurological disorders like schizophrenia.

"Our future research is exciting," Iossifov says. "If one of those theories or two of them prove to be true, then it opens different treatment strategies, which can, in the future, affect quite a lot of families."

In addition, this research offers helpful tools for educators and therapists. It may allow for earlier diagnoses and a better overall understanding of autism.

Related Information

Risk of Autism Among Younger Siblings of a Child with Autism: The risk of autism among younger siblings of a child with autism is greater with risk for boys greater than for girls, and risk is over 32% if the infant has more than one sibling with autism.
The Impact of Autism on Older Siblings: Possible early warning signs for autism spectrum disorders within families.
Autism Spectrum Disorders and Motor Skills in Children: Washington University study is the first to evaluate motor impairments in children with autism spectrum disorder and their siblings who do not have the disorder.
Language Delays in Siblings of Children with Autism: Siblings of children with autism have more frequent language delays and other subtle characteristics of the disorder.

Attribution/Source(s): This peer reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by Cold Spring Harbor Laboratory and published on 2023/05/22, this content may have been edited for style, clarity, or brevity. For further details or clarifications, Cold Spring Harbor Laboratory can be contacted at cshl.edu NOTE: Disabled World does not provide any warranties or endorsements related to this article.