Reveal SNP Microarray is a high density copy number array which enhances the detection of chromosome abnormalities. It can also detect copy neutral changes such as uniparental disomy (UPD) and consanguinity. Both of these are associated with an increase in risk for autosomal recessive conditions, and UPD is also associated with imprinting disorders and effects of early gestational trisomy mosaicism. Clinical Indications: Individuals with non-syndromic congenital anomalies, dysmorphic features, developmental delay, intellectual disability, and/or autism spectrum disorders (ASD). Individuals with any of the above when previous chromosome analysis was normal. Phenotypically abnormal individuals with apparently balanced chromosome rearrangements or unidentified marker chromosomes.
Detects chromosomal imbalance that may be present in newborns or children with developmental delay/congenital anomalies/autism; genotyping in the array allows detection of uniparental disomy of autosomes, the presence of consanguinity, and the associated genomic location of recessive allele risk.
DNA extraction; interpretation
Whole genome SNP-based copy number microarray analysis targeting 2.695 million copy number and allele-specific genome sites
Whole blood or LabCorp buccal swab kit (buccal swab collection kit contains instructions for use of a buccal swab).
4 mL or LabCorp buccal swab kit
2 mL (neonatal) (Note: This volume does not allow for repeat testing.) or two buccal swabs
Green-top (heparin) tube (preferred), yellow-top (ACD) tube, or lavender-top (EDTA) tube or LabCorp buccal swab kit.
Pertinent medical findings must accompany the test request form. A Clinical Questionnaire for Reveal SNP Microarray - Pediatric must be completed.
This test may also be performed on adults. When a child tested with this assay is found to have an abnormal array of unknown clinical significance that may be clarified through parental testing, there will be no charge associated with the follow-up parental testing that is based on the child's results. All other parental follow-up testing will be charged, including (but not limited to) autism susceptibility regions, known microdeletions/microduplications, autosomal recessive deletions/duplications, and large copy-number changes with likely pathogenic significance. The child's abnormal array results will indicate whether parental testing will be performed at no charge and will include the appropriate parental follow-up test number.
Causes for Rejection
Quantity not sufficient for analysis; wet buccal swab
Maintain specimen at room temperature.
Positive evaluation criteria include: DNA copy gain/loss within known clinically significant gene region of 50 kb or greater. DNA copy number loss >200 kb or gain >500 kb outside known clinically significant regions with at least one OMIM annotated gene or within a region of clear clinical significance. UPD testing is recommended for patient results demonstrating a long contiguous region of homozygosity in a single chromosome >20 Mb interstitially or >10 Mb telomerically (15 and 8 Mb, respectively, for imprinted chromosomes). Contiguous homozygosity >10 Mb within multiple chromosomes suggests common descent. These regions of potential recessive allele risk are designated.
This assay does not detect balanced rearrangements and low-level mosaicism.