Genetics and Assisted Reproduction mimic the way the psychologic consultation looks
With the advent of pre-embryo genetic testing (PGT) we are now able to diagnose genetic problems before an embryo is transferred to the female partner. This technology has enormous implications in terms of avoiding decisions to terminate a pregnancy. PGT is performed by the removal of anywhere from 2-6 cells from the trophectoderm, this is the area of the day five embryo that is destined to form the placenta – biopsying this area does not harm the inner cell mass destined to develop into the fetus. There is some uncertainty as to how accurately cells from the trophectoderm reflect those in the inner cell mass. While this correlation is believed to be close to 100% it is not likely to be 100% in any particular embryo. Therefore, any diagnosis made from biopsying the trophectoderm should ideally be confirmed with followup screening in the form of amniocentesis at 15-18 weeks. When 20% or less of the biopsied cells are abnormal this is considered a chromosomally normal or euploid embryo. When 20-40% of the cells are abnormal this is considered a low grade mosaic embryo. When 40-80% of the biopsied cells are abnormal this is considered a high grade mosaic embryo. When more than 80% of the cells are abnormal this is considered aneuploid, i.e., clearly abnormal. Most IVF programs do not transfer aneuploid or high grade mosaic embryos, many will not transfer low grade mosaic embryos. Even low grade mosaic embryos have an increased chance of not leading to a pregnancy, miscarriage or to a developmentally abnormal pregnancy. Transfer of a low grade mosaic embryo should occur when there is no option of having a clearly euploid embryo to transfer. The transfer of a low grade mosaic embryo should occur with appropriate genetic consultation. Followup genetic amniocentesis should be performed.
When a genetic disorder such as sickle cell disease, Tay Sachs disease runs in a family it can be transmitted in a number of ways. Sometimes transmission occurs from one generation to the next, sometimes it skips a generation, sometimes transmission involves only one gender. Genetic counseling looking at the particular disorder and family pedigree can predict the risk of a couple having an affected child. Pre-embryo genetic testing can diagnose which embryos would actually transmit the condition.
The Atwal Clinic
Dr. Paldeep S. Atwal is the founder of The Atwal Clinic and is Board Certified in Clinical and Medical Biochemical Genetics. Dr. Atwal has extensive experience in diagnosis and management of all genetic conditions, including metabolic disorders. The Atwal Clinic is located at 6821 Southpoint Drive N, Suite 118 Jacksonville, FL 32216. Their telephone number is 904-364-9985. Their website, www.AtwalClinic.com, is also available for scheduling appointments.