Preimplantation
Genetic Diagnosis (PGD)
North
Shore Fertility's preimplantation genetic diagnosis
program (PGD) is on of the most extensive in the area
for couples who are at risk of transmitting genetic
diseases to their children. Diseases such as hemophilia,
cystic fibrosis, sickle cell anemia, and others have
a genetic or "chromosomal" basis. In the
past, "carrier" couples ran a high risk
(in some cases 50%) of transferring serious diseases
to their offspring and often did not attempt pregnancy.
We receive referrals for PGD from throughout the world.
When
PGD is used with in vitro fertilization it allows
the physician to determine if the pre-embryos are
normal, and advise the couple, before it is placed
back into the uterus.
The "at risk couple" undergoes a standard
IVF cycle and the resultant eggs are combined with
sperm and placed in an incubator. Normally, the father
contributes 23 chromosomes and the mother contributes
23. Sometimes this "combining" process occurs
improperly leading to potential birth defects or pregnancy
loss. Chromosomes may also be damaged.
In
PGD, once the embryos have reached the stage where
they are ready to be transferred, a biopsy is taken
by "drilling" a hole in the outer membrane
(zona pellucida) and removing a single cell. This
cell is analyzed for chromosomal abnormalities using
a procedure termed fluorescent in situ hybridization
(FISH). All cells in the body contain the same chromosomal
structure (except reproductive cells formed through
meiosis) and the biopsy is a reflection of the entire
organism.
The
chromosomes are counted, the number of X and Y chromosomes
is verified, and other structural problems can be
identified. The end result is the transfer of embryos
known to be chromosomally normal.
PGD can be used to screen for the following diseases:
| Cystic
Fibrosis |
Retinoblastoma
|
Epidermolysis
Bullosa |
| Sickle
Cell Anemia |
Tay
Sachs Disease |
P53
Oncogene Mutation |
| Thalassemia |
Hemophilia
A and B |
OTC
Deficiency |
| Myotonic
Dystrophy |
HLA
Genotyping |
Neurofibromatosis
(NF1 & NF2) |
| Fragile
X Syndrome |
Fanconi
Anemia |
Multiple
Epiphyseal Dysplasia |
| Phenylketonuria
(PKU) |
Alzheimer's
(APP gene) |
Achondroplasia |
| X-Linked
Hydrocephalus |
ADA
Deficiency |
Chromosomal
Translocations |
| Gaucher's
Disease |
Retinitis
Pigmentosa |
|
| Age
Related Aneuploidy |
LCAD |
|
