Lack of evidence for genomic instability in autistic children as measured by the cytokinesis-block micronucleus cytome assay.
Micronuclei don’t flag genomic instability in autism, so cross chromosomal breakage off your causal checklist.
01Research in Context
What this study did
Austin et al. (2015) drew blood from autistic children, their brothers or sisters, and unrelated kids. They used the CBMN-cyt assay to count tiny broken chromosome pieces called micronuclei. The test looks for signs that DNA is unstable.
What they found
Micronuclei levels were the same in all three groups. Genomic instability was not higher in autism. The only odd result: vitamin B2 was slightly elevated in the autism group.
How this fits with other research
Older papers saw hints of trouble. Green et al. (1986) and Konstantareas et al. (1999) found rare, large chromosome changes in some autistic children with intellectual disability. Those studies used older karyotype pictures that only catch big breaks.
Hutchins et al. (2020) used a sharper tool, chromosome microarray, and found small causative changes in 22 % of girls with idiopathic autism. The CBMN-cyt assay is broader but less fine-grained; it measures random daily damage, not fixed mutations. The null result here does not clash with Hutchins et al. (2020) — it simply asks a different question.
Wang et al. (2025) recently warned that most biological markers, including genetic ones, are still too shaky for early autism diagnosis. Austin et al. (2015) now joins that chorus: micronuclei are not a useful marker either.
Why it matters
If a family asks whether their autistic child has fragile DNA, you can say current evidence says no. Micronucleus testing won’t explain behaviors or guide therapy. Spend your assessment time on skill-based tools, not this lab test.
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02At a glance
03Original abstract
Autism spectrum disorders are a set of neurodevelopmental disorders that are highly hereditable. Increased genomic instability has been observed in other heritable paediatric neurobiological disorders; therefore, the aim of our study was to test the hypothesis that DNA damage is increased in children with autism and that B vitamin status may explain variations in genome integrity between autistic and normal children. We compared 35 children with autism, 27 of their siblings without autism and 25 age- and gender-matched community controls for genomic stability using the cytokinesis-block micronucleus cytome (CBMN-cyt) assay, B vitamins and homocysteine, as well as autism-related behaviours. It was found that there were no differences in CBMN-cyt biomarkers between the three groups. Vitamin B2 was significantly raised in children with autism and their siblings compared with controls (P = 0.027 and P = 0.016 respectively) but there was no difference in other B vitamins or homocysteine. In conclusion, although replication using a larger cohort is needed, it appears unlikely that genomic instability is a feature of the aetiology of autism. We cannot rule out in utero effects or other types of DNA damage not measured by the CBMN-cyt assay.
Autism research : official journal of the International Society for Autism Research, 2015 · doi:10.1002/aur.1428