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Matthew Bower, MS University of Minnesota Ataxia Center. Ataxia -Genetics and family planning. The information provided by speakers in any presentation made as part of the 2012 NAF Annual Membership Meeting is for informational use only.
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Matthew Bower, MS University of Minnesota Ataxia Center Ataxia-Genetics and family planning
The information provided by speakers in any presentation made as part of the 2012 NAF Annual Membership Meeting is for informational use only. • NAF encourages all attendees to consult with their primary care provider, neurologist, or other health care provider about any advice, exercise, therapies, medication, treatment, nutritional supplement, or regimen that may have been mentioned as part of any presentation. • Products or services mentioned during these presentations does not imply endorsement by NAF. Disclaimer
Matt Bower, MS, CGC • The following personal financial relationships with commercial interests relevant to this presentation existed during the past 12 months: • No relationships to disclose or list Presenter Disclosures
Ataxia genetics are too complicated for a 30 minute talk! • I will be speaking in broad generalizations • Consult with your physician or genetic counselor about your specific questions Take-home points:
Plan ahead • Many testing options require advance knowledge of your genetic status Take Home points
Family planning decisions are personal decisions- there is no “right” answer. Take Home points
Genetics review- dominant inheritance SCA1-36 (and counting!) These men are both affected with ataxia
Genetics review- dominant inheritance SCA1-36 (and counting!) Each of these siblings has an independent 50% risk
Friedreich, AOA1, AOA2, AT, and others Genetics review- recessive inheritance These two sibilngs have ataxia
Genetics review- recessive inheritance Both parents are carriers
Genetics review- recessive inheritance These two siblings have a 2/3 (67%) carrier risk
Genetics review- recessive inheritance Carrier risk for spouses depends on how common the ataxia is in the general population
Diagnostic testing- Testing someone with symptoms to figure out the type of ataxia in your family. • This person may be you (if you have symptoms), or it may be another family member. • Genetic testing is only accurate if the type of ataxia in the family is known. • Important to obtain actual test results, if possible. Step 1- What kind of ataxia is in my family?
In order to determine if your children may be at risk, it may be important to determine your own genetic status • Dominant ataxias • If you have symptoms, you could have diagnostic testing. • If you are asymptomatic, you could have predictive testing. Step 2- What is my genetic status?
In order to determine if your children may be at risk, it may be important to determine your own genetic status • Recessive ataxias • Affected with the familial ataxia-diagnostic testing • Biological relatives of affected individuals (carrier testing) • Non-biological relatives of affected individuals (i.e. people who marry into the family) carrier testing Step 2- What is my genetic status?
Dominant ataxias • If you have the ataxia gene, your child will have a 50% risk (regardless of whether it is a boy or girl) • If you did not inherit the ataxia gene, then your children are not at risk (i.e. does not skip generations). • Recessive ataxias • If both parents are carriers, the risk to each child is 25% (regardless of whether it is a boy or girl) Step 3- What are risks to future children?
Having children without any genetic testing Adoption / Foster parenting Pregnancy with prenatal diagnosis In vitro pregnancy with donor egg donor sperm In vitro pregnancy with genetic testing (pre-implantation genetic diagnosis) Step 4- What are my options?
Definition- Genetic testing done during a pregnancy to determine if a fetus is affected with the familial ataxia • Two procedures are available: • Chorionic villus sampling (CVS) • Amniocentesis Prenatal diagnosis
amniocentesis • Amniotic fluid is removed using a thin needle. • Cells from amniotic fluid can be tested for the familial ataxia • Generally done after 15 weeks gestation • Small risk of miscarriage (< 0.5%)
CVS • Generally done 10-13 weeks gestation • Not as widely available as amniocentesis • Risk of miscarriage varies from center to center- generally <1%
If the father is affected with a dominant ataxia, or a carrier of a recessive ataxia, patients can utilize a donor sperm sample • Known unaffected relative • Anonymous donor • Does not require IVF procedures Intrauterine insemination with donor sperm
Sperm and egg are mixed in a petri dish to create embryos. In-vitro fertilization
IVF (all by itself) does not alter the risk for ataxia in children. If the mother is either affected with the ataxia, or is a carrier, couples can do in-vitro fertilization using an egg from a healthy donor. In-vitro fertilization with donor egg
Embryos created through IVF One cell from each embryo is tested to determine if the embryo is “affected” with the familial ataxia. Only “unaffected” embryos are transferred to the uterus. Pre-implantation genetic diagnosis
Pre-implantation genetic diagnosis (PGD) Braude, P., et al., Preimplantation genetic diagnosis, Nature Reviews Genetics 3, 941–955
Fetal DNA is known to be in mother’s blood during pregnancy • Tests have recently been developed to diagnose some specific fetal conditions from a maternal blood draw • No risk of miscarriage • Not yet available for conditions like ataxia. Non-invasive prenatal diagnosis
Having children without any genetic testing Adoption / Foster parenting Pregnancy with prenatal diagnosis In vitro pregnancy with donor egg donor sperm In vitro pregnancy with genetic testing (pre-implantation genetic diagnosis) Summary- What are my options?
Does my future child’s ataxia status have any bearing on my decision to have children? Importance of being the biological mother/father Financial- will insurance cover the costs of procedures? Are there medical risks with some of these technologies Emotional investment with in-vitro fertilization technologies. Step 5- What is right for me?