The Claim Going Around
A social media post declares that autism is linked to Neanderthal DNA present in modern humans. It sounds like the kind of thing that gets stretched far beyond what any single study could show - and in this case, there really is a study behind it. But "linked to Neanderthal DNA" flattens a much narrower, more careful finding into something that sounds far more sweeping.
The Real Study
Researchers Rini Pauly, Emily Casanova, and Alex Feltus published "Enrichment of a subset of Neanderthal polymorphisms in autistic probands and siblings" in Molecular Psychiatry (a Nature-group journal) in 2024. They analyzed genetic data from the SPARK autism research database, comparing it against reference population panels (GTEx and 1000 Genomes), across three distinct groups: Black non-Hispanic, White Hispanic, and White non-Hispanic participants.
What They Actually Found
The researchers identified roughly 25 Neanderthal-derived genetic variants tied to brain development that were overrepresented in autistic individuals compared to ethnically-matched controls. One specific variant, in the gene SLC37A1, was linked to epilepsy specifically within the White non-Hispanic group - epilepsy and autism frequently co-occur, making this a plausible, testable lead.
Not "More Neanderthal DNA" - Just Certain Variants
This is the detail the viral version drops entirely: autistic people do not carry more total Neanderthal ancestry than anyone else. Everyone with recent Eurasian ancestry carries roughly the same 2-3% Neanderthal DNA overall. What the study found is that a specific, small subset of Neanderthal-derived variants - not the overall amount - showed up more often in autistic participants.
The Part the Post Skips: It Depends Heavily on Ancestry
The effect was strikingly population-specific. A variant associated with autism in Black non-Hispanic participants showed no such association in White Hispanic participants, and vice versa. This actually makes biological sense: Neanderthal admixture itself varies significantly by ancestry - it is much lower or effectively absent in populations without significant recent Eurasian mixing. A single, universal "Neanderthal DNA causes autism" framing doesn't fit how the underlying genetics actually works.
What This Isn't
The researchers themselves describe these variants as weak and "susceptibility-modifying" - contributing factors, not deterministic causes. The study covered only the exome (the protein-coding portion of the genome), described by the authors as a first pass rather than a complete picture. As of this writing, the finding has not been independently replicated by another research group, and no specific effect sizes were reported in available coverage. This is early-stage, genuinely interesting research - not a settled mechanism.
Why This Fits a Bigger Pattern
This connects to something we've covered before: modern human evolution and psychiatric conditions increasingly show overlapping, complex genetic architecture rather than single, clean causes. Neanderthal-derived variants affecting depression risk, immune function, and now potentially autism susceptibility all point to the same idea - our evolutionary history left genetic traces that interact with modern conditions in ways researchers are still mapping out, population by population.
The Bigger Picture
A real, peer-reviewed study does exist here - this isn't a fabricated claim. But "autism is linked to Neanderthal DNA" implies something far more universal and settled than a preliminary, population-specific, exome-only finding involving a small subset of weak-effect variants. The honest version is more interesting precisely because it's more specific.
Sources: Pauly R, Casanova EL, Feltus FA. "Enrichment of a subset of Neanderthal polymorphisms in autistic probands and siblings," Molecular Psychiatry (2024).