IriSight™ CNV Analysis

IriSight™ CNV Analysis is a genetic test performed during pregnancy to look for chromosomal conditions in a fetus. It is similar to NIPT (noninvasive prenatal testing, also referred to as NIPS or noninvasive prenatal screening) and chromosomal microarray (CMA) tests, but there are important differences.

First, NIPT is predictive – it can only suggest that a fetus is at high or low risk of having a certain chromosomal condition. Both CMA tests and IriSight™ CNV Analysis are diagnostic tests that provide definitive answers.

Second, NIPT, CMA and IriSight™ CNV Analysis use different sequencing technologies that affect the type and size of chromosomal changes that can be detected. The table below provides a comparison.

IriSight™ Prenatal Analysis

IriSight™ Prenatal Analysis is a genetic test performed during pregnancy that goes beyond IriSight™ CNV Analysis to identify small sequence changes in a fetus that can cause early-onset genetic disorders such as cystic fibrosis. It is similar to carrier screening and exome testing, but there are important differences.

First, carrier screening does not test your baby – it can identify DNA changes that you or your baby’s father could pass on, but it doesn’t specifically reflect your baby’s genetic make up. Exome tests and IriSight™ Prenatal Analysis are diagnostic tests that provide definitive answers.

Second, exome testing and IriSight™ Prenatal Analysis use different sequencing technologies that affect the type and size of DNA changes that can be detected. The table below provides a comparison.

Prenatal testing differences

NIPT

CMA

IriSight™ CNV Analysis

Exome

IriSight™ Prenatal Analysis

Sequencing Technology

SNP technology: sequences <1% of DNA

SNP technology: sequences <1% of DNA

Genome technology: sequences >98% of DNA

Exome technology: sequences 1-2% of DNA

Genome technology: sequences >98% of DNA

Chromosomal changes that can be detected

Down syndrome, Edward syndrome, Patau syndrome

Trisomies 1-12, 14-17, 19-20, 22

Not detected

Monosomy X (Turner syndrome), XXY syndrome (Klinefelter syndrome), Triple X syndrome, XYY syndrome (Jacob's syndrome)

Microdeletions

Subset are detected

CNVs

Not detected

Detected with size limitations

Detected with size limitations

Inversions

Not detected

Varies

Not detected

Additional changes that can be detected

Small sequence changes

Not detected

Not detected

Not detected

Mitochondrial

Not detected

Not detected

Not detected

Varies

Repeat expansions

Not detected

Not detected

Not detected

Not detected

See IriSight™ CNV Analysis and IriSight™ Prenatal Analysis test specifications for more information.

Definitions

Trisomy – A condition where an extra copy of a complete chromosome is present

Monosomy – A condition where a complete chromosome is missing

Microdeletion – A type of DNA change where a portion of a chromosome is missing

CNV – A type of DNA change where a DNA segment is missing (deletion) or is present in extra copies (duplication)

Inversion – A type of DNA change where a DNA segment is present in reverse orientation or has been relocated to a different position within the genome

Small sequence change – A type of DNA change where a single base or small number of bases is altered

Mitochondrial – Changes in the mitochondrial genome

Repeat expansion – A type of DNA change where a sequence of bases is repeated in an expanded stretch

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