AMP case report: Advantages of SNP chromosomal microarray over conventional FISH and DNA tests for methylation-specific PCR-positive Prader-Willi syndrome

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Of note, SNP chromosomal microarray, as a follow-up test to MSPCR-positive PWS, is not intended to detect the “PWS-like phenotype”-associated cytogenomic rearrangements, such as an interstitial deletion of 6q16.2, 1p36 deletion, 16p11.2 deletion, duplication Xq27.2qter, and deletion 10q26, or mimics of parts of the PWS phenotype,2 unless these rearrangements are in addition to deletion 15q11.2q13.

The SNP chromosomal microarray analysis can lead to incidental findings. This possibility should be discussed during pretesting genetic counseling.

Finally, proband-only SNP chromosomal microarray analysis may detect abnormalities in 86 percent of PWS patients,² while trio SNP chromosomal microarray analysis may increase the detection rate to 97 percent.

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Acknowledgments: We wish to thank Gail Dunphy, Julie Boles, Sue Arnold, and James Malone for outstanding assistance with this work.

Dr. Xu is a clinical cytogeneticist and director of cytogenetics, Akron (Ohio) Children’s Hospital, and professor of pathology, Northeast Ohio Medical University. Dr. Warshawsky is a molecular pathologist and director of molecular diagnostics, Akron Children’s Hospital, and assistant professor of pathology, Northeast Ohio Medical University. Dr. Dougaparsad is a reproductive health specialist, Thermo Fisher Scientific, Santa Clara, Calif. Dr. Melver and Dr. Costin are medical geneticists at Akron Children’s Hospital.

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