Critical region within 22q11.2 linked to higher rate of autism spectrum disorder.
Caitlin C Clements, Tara L Wenger, Alisa R Zoltowski and 10 others
PMID 29090080WHAT IT FOUND
5 of 12 participants with deletions including LCR-A to B had autism, versus 0 of 8 with deletions not including that region, but the study did not confirm this difference.
This small genetic study does not show a treatment or screening change.
Key findings
015 of 12 participants with deletions involving LCR-A to B or LCR-A to C had autism, compared with 0 of 8 participants with deletions involving LCR-B to D or LCR-C to D; the authors reported this as a trend, not a confirmed difference.
027 of 29 participants with classic LCR-A to D duplications had autism, compared with 1 of 5 participants with nested LCR-B to D or LCR-C to D duplications; the rates were similar.
03On the Vineland-II adaptive behavior measure, where 100 is average, participants with deletions involving LCR-A to B had a composite mean of 85.7, compared with 103.8 for participants with deletions not involving that region, but the difference was not significant.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The deletion comparison was very small: 12 probands with deletions involving LCR-A to B or A to C and 8 probands with deletions involving LCR-B to D or C to D. The main result was a trend, not a confirmed difference; the significant result appeared only after adding related family members, which the authors said requires a larger sample without relatives. No nested duplications involving LCR-A to B were present, so the study could not test whether duplicating that region raises autism risk. Diagnosis depended on chart review, questionnaires, and some in-person evaluations rather than systematic prospective autism evaluation for all participants. Many patients had not completed recommended medical screening, so medical comorbidity rates may be underestimates. The study cannot separate the contribution of individual genes inside LCR-A to B, which contains approximately 25 genes. The two case studies are descriptive and cannot establish gene effects.
Declared interests
Funding was reported from the National Institute of Mental Health, Simons Foundation, National Institutes of Child and Human Development, Pennsylvania Department of Health, National Science Foundation, and Robert Wood Johnson Foundation. The text does not provide author conflict-of-interest declarations.
The easy way to misread this
Do not read the 41.7% versus 0% autism rates as proof that LCR-A to B deletions cause autism. The first comparison was reported as a trend, not a confirmed difference, and the significant result appeared only after adding related individuals.