Next-generation sequencing could enable IVF clinics to determine the chances of children developing diseases
The first IVF baby to have undergone an embryo selection using a procedure that can read every letter of the human genome has been born.
Connor Levy was born in the United States on May 18 after a Philadelphia couple had cells from their IVF embryos sent to specialists in Oxford, southern England, who checked them for gene abnormalities. The process helped their U.S. fertility clinic select embryos with the right number of chromosomes, which have a much higher chance of producing a healthy baby.
The birth demonstrates how next-generation sequencing (NGS), which was developed to read whole genomes quickly and cheaply, is poised to transform the selection of embryos in IVF clinics.
Though on this occasion scientists only looked at chromosomes — the structures that hold genes — the falling cost of whole-genome sequencing means doctors could soon read all the DNA of IVF embryos before choosing which to implant.
If doctors had a readout of a genome, they could judge the chances of the child developing certain diseases, such as cancer, heart disease or Alzheimer’s.
Marybeth Scheidts (36) and David Levy (41) had tried another fertility treatment three times without success before they signed up for IVF at Main Line Fertility, a clinic in Pennsylvania. As part of an international study with Dagan Wells, a fertility specialist at Oxford University, the couple were offered NGS to check their IVF embryos for abnormal chromosomes, which account for half of miscarriages.
The chances of an embryo having the wrong number of chromosomes rise with the mother’s age, and potentially with the father’s. Most of the time, embryos with abnormal chromosomes fail to implant. Those that do are usually miscarried. The portion that survive are born with genetic disorders, such as Down’s syndrome.
After treatment at the U.S. clinic, the couple had 13 embryos to choose from. Tests showed that while most looked healthy, only three had the right number of chromosomes. “It can’t make embryos better than they were in the beginning, but it can guide us to the best ones,” said Mr. Wells.
Details of the study were to be given at the European Society of Human Reproduction and Embryology meeting in London on Monday. — © Guardian Newspapers Limited, 2013