Definition

This SNP microarray based method can detect, beyond the large aneuploidies and unbalanced rearrangements above 5-10 Mb that classic karyotyping can see, microdeletions/microduplications, triploidy, uniparental isodisomy, and low-level mosaicism. ACOG and SMFM recommend that chromosomal microarray analysis (CMA) replace fetal karyotyping in cases with structural anomalies or fetal death; because it can be performed on uncultured DNA samples, the turnaround time is shorter than karyotyping.

Note: Pricing includes a maternal contamination test along with the material; the sample must be sent as EDTA blood. The test may not yield a result on products of conception; in this case the test is still billed.

Gene/region examined

*

Method

SNP Array

Accepted sample types

Cord blood (EDTA), Amniocentesis, CVS

Inheritance

Not applicable, this is a diagnostic method (it screens for inherited/de novo copy number changes in the fetal genome from a prenatal sample).

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Inheritance Patterns

Describes how a genetic condition is passed on within a family. There are five main patterns

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Carrier (Heterozygous / Homozygous)

Why it matters: In autosomal recessive inheritance, when each parent is a carrier (while both appear healthy), the chance of their child being born with the disease is 25% in each

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VUS (Variant of Uncertain Significance)

This is the situation where the test has detected a change in the DNA, but the role of this change in the development of disease is unconfirmed.

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How to Read a Genetic Test Result (Positive / Negative / VUS)

A genetic test result falls into three main categories

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Types of Genetic Tests

A genetic test is a type of medical test that detects changes in genes, chromosomes or proteins. Today there are more than 77,000 genetic tests available.

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