When
in vitro fertilization (IVF) is used to prevent having a pregnancy affected by a specific genetic disorder, it is one step of a larger process called
preimplantation genetic diagnosis (PGD). PGD is done after IVF to diagnose a genetic condition in an embryo before it is introduced into the uterus. When having PGD, only embryos known to be unaffected are introduced into the uterus for a possible pregnancy. PGD does not involve the modification of
genetic material (
gene therapy) to remove a
mutation from an affected embryo.
PGD typically requires that the specific, genetic
mutations responsible for a disorder in a family have been identified. Mutations may be identified in an affected family member, or in parents who are
carriers. Therefore, advanced planning and testing is needed.
While we are not aware of specific laboratories that offer PGD for Pierson syndrome, some laboratories that perform PGD are able to do "custom" testing for most types of mutations.
Gender selection, or sex selection, may be used during PGD with IVF for medical reasons to prevent genetic disorders known to affect only males, or known to be more severe in males (
X-linked disorders). Pierson syndrome is
inherited in an
autosomal recessive manner, affecting both sexes equally. Sometimes gender selection is "elective" when a specific gender is desired without obvious medical reasons.
As an alternative to IVF and PGD, it may be possible to find out in early pregnancy whether a fetus is affected. If the mutations in a family are known, prenatal
genetic testing may be possible during pregnancy. Genetic testing may be performed on a sample obtained by
chorionic villus sampling (at about 10 to 12 weeks gestation), or by
amniocentesis (usually performed at about 15 to 18 weeks gestation). If the condition is confirmed in the fetus after either method, planning for an affected child and/or pregnancy management options may be discussed with a health care provider.
Ultrasound may also be used as a
screening test to detect signs or symptoms of the disorder in an affected fetus. However, if no abnormalities are detected on ultrasound, the possibility that the fetus is or will be affected cannot be ruled out.
People interested in genetic testing,
prenatal diagnosis, and/or PGD should speak with a
genetic counselor or other genetics professional regarding their testing options. A genetics professional can help by:
- thoroughly evaluating the family history
- addressing questions and concerns
- assessing recurrence risks
- facilitating genetic testing if desired
- discussing reproductive options
Last updated: 3/24/2016
Yes. The
Genetic Testing Registry (GTR) provides information about the genetic tests available for Pierson syndrome. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
According to the GTR, genetic testing for Pierson syndrome may be available for diagnosis in a person suspected of having the condition,
carrier testing, and prenatal testing.
Last updated: 3/24/2016
Pierson syndrome is inherited in an
autosomal recessive manner.
[1] This means that to be affected, a person must have a
mutation in both copies of the responsible
gene in each
cell. Affected people inherit one mutated copy of the gene from each parent, who is referred to as a
carrier. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a:
- 25% (1 in 4) chance to be affected
- 50% (1 in 2) chance to be an unaffected carrier like each parent
- 25% chance to be unaffected and not be a carrier
Last updated: 3/24/2016
Last updated: 12/6/2017
