Chromosomal abnormalities that result in birth defects and genetic disorders like Down syndrome remain a significant health burden in the United States and throughout the world, with some current prenatal screening procedures invasive and a potential risk to mother and unborn child.
In a paper published online this week in the Early Edition of PNAS, a team of scientists at the University of California, San Diego School of Medicine and in China describe a new benchtop semiconductor sequencing procedure and newly developed bioinformatics software tools that are fast, accurate, portable, less expensive and can be completed without harm to mother or fetus.
"We believe this approach could become the standard of care for screening of prenatal chromosomal abnormalities," said Kang Zhang, MD, PhD, professor of ophthalmology, founding director of the Institute for Genomic Medicine at UC San Diego and a staff physician at the San Diego VA Healthcare System.
The incidence of chromosomal abnormalities in numbers or structure is one in 160 live births in the United States, higher in other countries. In China, for example, the rate is one in 60 live births. The effects of these abnormalities, known as aneuploidies, can be severe, from developmental delays and neurological disorders to infertility and death. The incidence rate rises with maternal age, most notably after age 35.
Current diagnoses of fetal aneuploidies often rely upon invasive tests that sample amniotic fluid or placental tissues for fetal DNA that can then be analyzed using a variety of complex and expensive methods, including full karyotyping in which the entire set of chromosomes is viewed microscopically. While highly reliable, these invasive tests may cause infections in the pregnant woman and pose as much as a 1 percent risk of miscarriage and fetal loss. Results are not available for one to two weeks, extending anxiety for families waiting for information.
|Contact: Scott LaFee|
University of California - San Diego