Unlocking Autism’s Genetic Puzzle: What a New Study of Families Reveals
I have 2 children, one with ADHD, one with Autism. I often "joke" with my husband about which one of us is ADHD, and which one is Autistic?? I say this because as a child I was held back in 1st grade due to a "developmental disability" I was tested several times in first grade because I couldn't read (I also was raised by 2 blind parents) later on in 6th grade I tested as "gifted" go figure?! My husband is very clearly ADHD however he also has a sister who has a daughter with autism. So I strongly believe that there are more people in our families who have "neurodivergent traits" than we realize! Recent research published in PNAS (August 1, 2023) https://www.pnas.org/doi/10.1073/pnas.2215632120 sheds light on the complex genetic basis of autism spectrum disorder (ASD) by examining families where two or more children are autistic. This largest-ever study of “multiplex” families offers fresh insight into how both rare and common genes work together to influence ASD.What's at the Heart of the Study? - Researchers sequenced the entire genomes of 4,551 people across 1,004 families where at least two siblings are autistic. - The goal? To untangle the relative role of rare inherited mutations (passed from parents) and polygenic risk—the small, combined effects of many common genes in ASD. Discovering New Driver Genes - They pinpointed seven new genes that hadn’t previously been linked to autism. - All told, the study supported 74 autism-associated genes in their group; once combined with earlier work, that number rose to 152 genes. - A Double Push: Rare Variants + Polygenic Risk - Children with ASD had more rare, damaging mutations in known autism-related genes compared to their non-autistic siblings. - Additionally, when researchers calculated the polygenic score (PGS) a number that reflects accumulated common-gene risk, they found that non-autistic parents overtransmitted higher polygenic risk to their autistic kids, especially those with rare inherited mutations. In simpler terms, rare and common genetic risks team up to tip the scale toward autism, even if parents carry the mutations but didn’t develop ASD themselves.