Comparison of prenatal genetic testing methods

Goal	Karyotype (G-banded)	CMA without SNPs	CMA with SNPs	Single gene sequencing test
Test can be performed on "direct prep" and does not require cell culture	No	Yes	Yes	Yes
Test can detect point mutation(s) for a single gene disorder	No	No	No	Yes
Test can detect balanced structural rearrangement (eg, balanced translocation or balanced inversion, ring chromosome with no loss of genomic material)	Yes	No	No	No
Test can detect unbalanced structural rearrangement (eg, unbalanced translocation, ring chromosome with loss of some material)	Yes	Yes	Yes	No
Test can detect copy gains/losses larger than 3 to 10 Mb, including whole chromosome aneuploidy	Yes	Yes	Yes	No
Test can detect copy gains/losses smaller than 3 to 10 Mb (microdeletion and microduplication syndromes)	No	Yes	Yes	No
Test can detect isochromosomes	Yes	Yes	Yes	No
Test can detect low-level mosaicism (approximately 10 to 15% mosaicism) for chromosome imbalance	Yes	No^*	Yes^¶	No
Test can detect triploidy	Yes	No	Yes	No
Test can identify origin of small-marker chromosome	No^Δ	Yes	Yes	No
Test can detect uniparental disomy due to isodisomy (NOTE: At least half of all uniparental disomy cases are heterodisomy and would not be detected)	No	No	Yes	No

NOTE: There are overgeneralizations here; certain sequencing approaches, such as whole genome sequencing, can detect mosaicism, isodisomy, and even copy number changes. It is not a widespread clinical test yet.

CMA: chromosomal microarray; Mb: megabase; SNP: single nucleotide polymorphism.

* CMA without SNPs can detect mosaicism in the range of approximately 30% or higher.

¶ CMA with SNPs performs as well as or better than a G-banded karyotype. The sensitivity of detection may vary depending on the density of SNP probe coverage.

Δ G-banded karyotype can identify the presence of a small marker chromosome but typically cannot determine which chromosome is involved.

Graphic 109837 Version 4.0

خرید پکیج

Comparison of prenatal genetic testing methods