Chromosomes in autism and related pervasive developmental disorders: a cytogenetic study.
Chromosome tests catch rare but important genetic causes in kids with PDDs, especially PDD-NOS.
01Research in Context
What this study did
Doctors looked at the chromosomes of 92 kids with PDDs.
They used blood tests and microscopes to spot any extra, missing, or broken pieces.
The group had classic autism, PDD-NOS, and other related delays.
What they found
Only the kids out of 92 had clear chromosome problems.
One child with classic autism had four copies of chromosome 15 instead of two.
The other two kids had different changes and both carried a PDD-NOS label.
How this fits with other research
Estécio et al. (2002) ran the same kind of screen in Brazil and found a large share had chromosome issues.
The higher rate may come from different lab methods or the kids they chose to test.
Walley et al. (2005) later showed that extra 15q material can indeed lead to PDD-NOS, backing the target’s single case.
Green et al. (1986) had already urged chromosome checks for autistic kids with low IQ, so the 1998 study simply tested that advice on a larger scale.
Why it matters
Even a low a large share yield matters when the test is simple and the answers guide medical care.
If you serve a child with unexplained delays plus autism or PDD-NOS, ask the pediatrician for a genetic referral.
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02At a glance
03Original abstract
Few studies have examined the occurrence of chromosome abnormalities in a large sample of patients with autism and related pervasive developmental disorders (PDDs). In the present report, the authors examined a consecutive series of 92 children with PDDs (DSM-III-R; 75 males and 17 females). A cytogenetic examination, including growth in folate deficient medium, was performed in all cases. Three patients (3.2%) (two females and one male) showed chromosome abnormalities: deletion of the long arm of chromosome 8; tetrasomy of chromosome 15; and XYY syndrome. Only the subject who had tetrasomy 15 met the criteria for autistic disorder, while the other were diagnosed as suffering from a PDD not otherwise specified (PDDNOS). Another patient showed an abnormal fragile site at Xq27 in three out of 100 cells. However, subsequent molecular studies did not confirm the presence of fragile-X syndrome. These results suggest that chromosome abnormalities are uncommon in traditional autism and may be relatively more common in people with PDDNOS.
Journal of intellectual disability research : JIDR, 1998 · doi:10.1046/j.1365-2788.1998.00091.x