Select ways that a baby can be born with a disease despite preimplantation genetic diagnosis.
a. test for presence of a disease allele common in family
test for alleles that code for targets of disease therapy
indicate if individuals are heterozygous carriers of disease alleles
b. Genes must be delivered only to cells that express the faulty alleles.
Virus vectors can trigger an immune reaction.
The new DNA can induce mutations that cause cancer.
c. PCR is extremely sensitive such that stray DNA can indicate a false result.
Technicians can make an error.
Only the most common mutations causing a disease are detected.
d. Tests that reveal a high risk of cancer may cause anxiety or depression.
PGD is expensive and may only be possible for the wealthy.
Parents may use genetic testing to select for desirable traits in embryos.