Expanded Carrier Screen (283 Genes)
Related Gene(s): View a full list of genes screened for
Sema4 Expanded Carrier Screen (ECS) is one of the most comprehensive carrier screens available. It screens for inherited disorders associated with 283 genes, including many conditions that are prevalent in people of certain ethnic backgrounds. For example, our Expanded Carrier Screen includes a Comprehensive Jewish Carrier Screen for 101 genes.
Nine testing technologies are used in parallel to ensure the highest detection rate for each gene based on gene-specific mutation mechanism.
- High-throughput, next-generation sequencing (NGS) is performed to examine multiple genes at once. Additionally, a custom bioinformatic algorithm is used to analyze this data in order to identify copy number variants (CNVs). Pathogenic or likely pathogenic deletions and duplications of 2 or more exons in length will be confirmed and reported. Additionally, single-exon pathogenic or likely pathogenic CNVs will also be reported when detected and confirmed
- Long-range polymerase chain reaction is used to capture the functional gene for accurate analysis of genes with known pseudogenes, including CYP21A2, GBA, HBA1, and HBA2
- Multiplex ligation-dependent probe amplification (MLPA) is used to detect copy number changes for congenital adrenal hyperplasia, Gaucher disease (when indicated), spinal muscular atrophy, alpha-thalassemia, and Duchenne and Becker muscular dystrophy
- Fragile X CGG repeat analysis is performed by PCR amplification followed by capillary electrophoresis for allele sizing. Samples positive for FMR1 CGG repeats in the premutation or full mutation size ranges are further evaluated by Southern blot analysis
- Genotyping analysis is used to identify or confirm variants that are complex in nature or are present in low copy repeats
- Tay-Sachs enzyme testing is a biochemical assay used to detect carriers of Tay-Sachs disease that may be missed by molecular testing
- Sanger sequencing may be used for select genes on the panel due to inadequate next-generation sequence coverage or for confirmation of variants identified by NGS
- Exon array and/or qPCR may be performed to confirm CNVs identified by bioinformatic analysis of the NGS data
Our carrier screening technologies are >95% accurate. A negative test result for any given disease does not exclude an individual from being a carrier for that disease, but only reduces the risk of being a carrier. The patient may still have a pathogenic variant that was not identified by this testing. Please refer to the residual risk table to determine the risk following a negative result.
With the Expanded Carrier Screen, carrier screening may be easily customized to address specific clinical needs. Testing can be performed for all 283 genes, a smaller subset of genes, or even just one gene. To learn more, explore the full list of genes that this test screens for.
For prenatal samples, please contact our laboratory at 800-298-6470 for more information.
- Blood: One 5-10 mL ACD tube (yellow top) and two 5-10 mL EDTA tubes (lavender top)
- Saliva: Saliva specimens are accepted in Oragene DNA (OG-500) kits by DNA Genotek. Please note that Tay Sachs enzyme analysis cannot be performed on saliva
- If carrier screening was previously performed through Sema4, reanalysis and/or test enhancements may be ordered without providing an additional specimen. Please contact the laboratory to determine if an additional specimen is required
- Ship at room temperature
- 10-14 days from receipt of specimen
Carrier Screening Clinical Information Sheet