Embryo screening to help parents with disorders
The China Post news staff
August 18, 2009, 9:27 am TWN
TAIPEI, Taiwan -- In a development sure to instill hope for those with genetic disorders, doctors at the Chang Gung Medical Foundation (CGMF) yesterday touted the nation's first case of embryo screening that played a definitive role in ensuring a successful pregnancy, local media reported.
Physician Chen Jun-kai with the CGMF Reproductive Center said the testing procedure enabled a couple bearing the same recessive genetic defect to deliver a pair of healthy twins.
The husband and wife were both carriers of thalassemia, a genetic defect that causes anemia, Chen said.
He added they did not realize they were carriers until two years ago when a prenatal blood test determined the fetus had severe thalassemia.
Given that the condition was life threatening, the wife underwent induced abortion during her fifth month of pregnancy, the doctor said.
Chen said there are many couples that share the same predicament in Taiwan, noting that five to eight percent of the population is carrying the thalassemia trait.
When both parents are genetic carriers, there is a 25 percent chance that each pregnancy will result in an affected child, Chen indicated.
He said prior to the introduction of the procedure, couples were merely banking on the odds every time they sought to get pregnant, fearing that the baby may inherit the condition.
According to CGMF, the recent development of embryo screening allows for the extraction of one to two cells to be analyzed, and embryos with the favorable characteristics could then be implanted in a woman's uterus to develop into a child as part of an in vitro fertilization procedure.
Not only does a healthy embryo lower the likelihood of chromosome mutation which eventually evolves into genetic disorders, it would also increase the mother's chances of getting pregnant.
Chen went on to say that the screening would help detect Down syndrome in older pregnant women, osteogenesis imperfecta, commonly known as “brittle bones disease,” thalassemia and neurofibromatosis, a genetically-inherited disease in which nerve tissues grow tumors.
With other conditions that would rely on more mature technology such as muscular dystrophy or adrenoleukodystrophy (ALD), a rare disorder that leads to progressive brain damage, the hospital would also be able to seek assistance from foreign medical facilities to complete diagnosis, Chen said.
As embryo screening requires in vitro fertilization, prospective couples would be required to pay NT$80,000 to NT$120,000 for the procedure and another NT$80,000 to NT$150,000 in testing fee, according to CGMF.
Chen added that the usual test tube baby procedure sees a success rate of 50 percent but that the odds decrease significantly for women over 37 in age.