New prenatal genetic test is more powerful

Testing a developing fetus' DNA via chromosomal microarray gives more information about disorders than standard prenatal testing, U.S. researchers say. The researchers, led by Dr. Ronald Wapner, director of reproductive genetics at NewYork-Presbyterian Hospital/Columbia University Medical Center and of Columbia University College of Physicians and Surgeons, found that in women having routine prenatal diagnosis, chromosomal microarray detected additional genetic abnormalities in about 1-in-70 fetal samples that had a normal karyotype. When a birth defect was imaged by ultrasound, chromosomal microarray found additional important genetic information in 6 percent of cases and these results suggested that chromosomal microarray may soon replace karyotyping for prenatal testing, Wapner said. "Why would anyone want to continue to use the standard method, which gives only part of the answer?" Wapner asked. "However, we will have to carefully transition this information into clinical practice-to educate physicians and patients, develop guidelines for its use, and learn how to best use it to improve care." Wapner led the 34-center study funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The results of the 4,000-plus-participant clinical study were presented at the 32nd annual meeting of the Society for Maternal-Fetal Medicine in Dallas. The study was recently published in the American Journal of Obstetrics & Gynecology.