Biomedical Engineering Reference
In-Depth Information
in 2005, a 97-99 percent success rate of obtaining cell biopsies for PGD
was reported, and a diagnosis of genetically healthy or abnormal was ob-
tained for 86 percent of the biopsied cells. Also in 2005, harvard physician
and bioethicist sigal Klipstein (2005) noted that PGD biotechnology is ush-
ering in a new era of predictive medicine that may ultimately supersede cu-
rative and preventive medicine in effectiveness and as a first choice in hu-
mankind's battle against disease. A major benefit of PGD is that couples at
risk for having children with a genetic disease can bring to term a disease-
free baby without resorting to prenatal, in utero diagnosis and pregnancy
termination.
How Is PGD Now Used?
Currently, the most prevalent use for PGD is to prevent the birth of chil-
dren with lethal or debilitating genetic diseases. in rare instances PGD
is used for gender selection or to produce savior siblings, both discussed
later in this chapter. Genetic diseases commonly diagnosed by PGD in-
clude cystic fibrosis, Tay-sachs disease, Duchenne's muscular dystrophy,
and Down syndrome. PGD is also used to diagnose late-onset diseases like
huntington disease and to identify embryos that would produce individu-
als with genetic predispositions for Alzheimer's disease and certain forms
of cancer. Table 3.1 lists some of the many diseases and genetic conditions
detectable by PGD.
The great power of PGD to prevent births of maldeveloped infants
will soon be matched by equally extraordinary predictive powers for both
disease- and non-disease-causing genetic conditions. DnA
base sequences
(i.e., the order of A, T, G, and Cs) are known for over twelve thousand
genes that are inherited at predictable frequencies.
2
several hundred of
these genes are linked to specific disease and non-disease traits (morpho-
logical, behavioral, and physiological), and more such linkages are discov-
ered weekly. Theoretically, PGD could be used to select for the presence
or absence of any one of over twelve thousand genes, giving the proce-
dure the potential for an almost unfathomable expansion into the realm of
Search WWH ::
Custom Search