Welcome to Kara Schmidt, PA and Registered Dietician for Infant Child & Adolescent Neurology

Autism Consortium study in Pediatrics shows CMA finds more genetic abnormalities than current tests

Editorial Note: This news is exciting in that it has hit the main press and that novel geneteic changes of uncertain significance are mentioned..

1) My clinical experience is consistent with these findings. I have been using microarray and newer standardized tests for 4 years. The microarray methodology keeps changing too. This year's test is better than the one that was available four years ago.

2) While highly provocative to those of us who follow the science, don't get too immediately excited about the practical implications of the copy number changes. The two copy number changes below appear to be recurrent but not linked to a known condition. If you search 16p11.2 on pubmed, you find links to epilepsy, obesity ovarian failure, schizophrenia and many more conditions. Single genes can be involved in widely different processes in development and everyday biological functions.

"With the exception of recurrent deletion and duplication of chromosome 16p11.2 and 15q13.2q13.3, most copy-number changes were unique or identified in only a small subset of patients."

In the end, this is a story that is being written every day and the truth is that we don't know what the ending will be.

Autism Consortium study in Pediatrics shows CMA finds more genetic abnormalities than current tests

Consortium recommends CMA be adopted as first-line diagnostic

The study, a collaboration between the Autism Consortium and Children's Hospital Boston, led by Consortium members Bai-Lin Wu, David Miller, Kira Dies, and Yiping Shen, examined 933 families (children and parents) who received clinical genetic testing for a diagnosis of Autism Spectrum Disorder (ASD) between January 2006 and December 2008. The researchers compared the findings from three clinical genetic tests: G-banded karyotype and fragile X testing, the current standard battery of genetic testing, and chromosomal microarray analysis, for which testing guidelines have not yet been established. Chromosomal microarray analysis is similar to a karyotype, but can find much smaller chromosomal deletions and duplications.

The results showed that chromosomal microarray analysis identified more genetic abnormalities associated with autism than the standard testing methods combined:

• Standard testing method G-banded karyotype testing yielded abnormal results in 19/852 patients (2.23%)
• Standard testing method Fragile X testing results were abnormal in 4/861 patients (0.46%)
• In contrast, chromosomal microarray analysis (CMA) identified deletions or duplications in 154/848 (18.2%) patients and 59/848 (7.0%) were clearly abnormal.
• As a result, chromosomal microarray was better than a karyotype for all but a small number of patients with balanced rearrangements, and those were not necessarily a cause of ASD.
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http://pediatrics.aappublications.org/cgi/content/abstract/peds.2009-1684v1

http://www.autismconsortium.org/press-releases/press-release-clinical-genetic-testing-in-asds.html