Prenatal Counseling

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January 2007 · Vol. 19, No. 01

UPDATE

NEW DEVELOPMENTS THAT ARE CHANGING PATIENT CARE

“Molecular karyotyping” opens a new avenue of prenatal diagnosis

Fast Track

Submicroscopic abnormalities will be detected with increasing frequency
The role of chromosomal abnormalities in 1st-trimester fetal loss will be better defined

Five years from now, look for array CGH to provide:

Faster detection of aneuploidy
Routine assessment of more disorders from fetal cells

So-called copy number polymorphisms are common in molecular karyotyping but often of no clinical significance

An imbalance in the genome of the fetus may play a larger role than we’ve thought in 1st-trimester loss

IN THIS ARTICLE

Deletions and duplications on chromosomes occur as often as 1 of every 1,000 births
Array CGH technology provides results from uncultured cells

Louise Wilkins-Haug, MD, PhD

Medical Director, Center for Fetal Medicine, Brigham and Women’s Hospital, and Associate Professor and Division Director, Maternal-Fetal Medicine and Reproductive Genetics, Department of Obstetrics, Gynecology and Reproductive Biology, Harvard Medical School, Boston

Prenatal diagnosis became a reality almost 40 years ago, when advances in microscopy and cell culture made it possible to examine chromosomes in fetal cells drawn from amniotic fluid—the familiar karyotype analysis. Technical advances continue to sharpen the resolution of routine karyotype analysis on amniotic fluid or a specimen of chorionic villus, and to raise the level of detail obtained from such a study.

Yet examining chromosomes by light microscopy remains time- and labor-intensive. A cell culture typically requires 2 weeks before growth of cells is sufficient to undertake a karyotype analysis—after which the microscopic evaluation requires further time and significant skill to perform.

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