Whole Genome Analysis of Dizygotic Twins With Autism Reveals Prevalent Transposon Insertion Within Neuronal Regulatory Elements: Potential Implications for Disease Etiology and Clinical Assessment.
A male-only LRFN5 pattern shaped by jumping DNA gives us a fresh genetic clue for why boys face higher autism risk.
01Research in Context
What this study did
Okay et al. (2023) mapped the entire DNA of boy-girl twins with autism. They hunted for bits of jumping DNA, called transposons, that had landed inside genes that turn brain cells on and off.
The team paid special attention to a gene named LRFN5. They checked if special patterns around this gene lined up with autism risk.
What they found
Only the boys carried a unique LRFN5 shape. This shape sits next to a transposon and may switch the gene off through epigenetic tags.
The same area showed small missing chunks in other boys with autism. This points to a boy-only genetic hotspot that could one day be spotted with a cheek-swab test.
How this fits with other research
Talebizadeh et al. (2019) also found jumping DNA at work, but in girls. They showed that skewed X-inactivation wakes up a long RNA that touches the KDM5C gene. Together, the two papers say transposons can nudge autism risk in different ways for each sex.
Scaccabarozzi et al. (2025) took the idea further. They split autism by IQ and found groups carry different harmful variants in brain modules. Their work tells us LRFN5 is only one brick in a bigger variant wall that shapes how autism looks.
Jarmolowicz et al. (2008) earlier saw spotty methylation at the MECP2 gene in autism brains. Kaan now shows a similar local epigenetic glitch at LRFN5, giving us a second clear address where tiny chemical tags may matter.
Why it matters
You now have a concrete example to explain to families why autism can run in twins yet look different in boys and girls. When you write reports, you can note that new genetic panels may soon include LRFN5 for boys. Keep an eye on epigenetic add-ons; they could guide earlier referral for baby brothers of autistic girls even when standard DNA tests come back normal.
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02At a glance
03Original abstract
LRFN5 is a regulator of synaptic development and the only gene in a 5.4 Mb mammalian-specific conserved topologically associating domain (TAD); the LRFN5 locus. An association between locus structural changes and developmental delay (DD) and/or autism was suggested by several cases in DECIPHER and own records. More significantly, we found that maternal inheritance of a specific LRFN5 locus haplotype segregated with an identical type of autism in distantly related males. This autism-susceptibility haplotype had a specific TAD pattern. We also found a male/female quantitative difference in the amount histone-3-lysine-9-associated chromatin around the LRFN5 gene itself (p < 0.01), possibly related to the male-restricted autism susceptibility. To better understand locus behavior, the prevalence of a 60 kb deletion polymorphism was investigated. Surprisingly, in three cohorts of individuals with DD (n = 8757), the number of deletion heterozygotes was 20%-26% lower than expected from Hardy-Weinberg equilibrium. This suggests allelic interaction, also because the conversions from heterozygosity to wild-type or deletion homozygosity were of equal magnitudes. Remarkably, in a control group of medical students (n = 1416), such conversions were three times more common (p = 0.00001), suggesting a regulatory role of this allelic interaction. Taken together, LRFN5 regulation appears unusually complex, and LRFN5 dysregulation could be an epigenetic cause of autism. LAY SUMMARY: LRFN5 is involved with communication between brain cells. The gene sits alone in a huge genomic niche, called the LRFN5 locus, of complex structure and high mammalian conservation. We have found that a specific locus structure increases autism susceptibility in males, but we do not yet know how common this epigenetic cause of autism is. It is, however, a cause that potentially could explain why higher-functioning autism is more common in males than females.
Journal of autism and developmental disorders, 2023 · doi:10.1073/pnas.0705803104