Some people may feel strongly about knowing their options as a means to reduce cancer risks in future generations, while others may choose not to do anything in terms of family planning, and both of these are valid choices.
Inheritance The chance of passing on Lynch syndrome to a child (or not passing it on) depends on the genetic status of both parents. These chances are shown below (also, see diagram to right).
When one parent has Lynch syndrome | Chance
of having a child affected with Lynch syndrome | 50% | | Chance
of having a child without Lynch syndrome | 50% |
When both parents have Lynch syndrome (different gene) | Chance of having a child affected with Lynch syndrome | 75% | | Chance of having a child without Lynch syndrome | 25% |
When both parents have Lynch syndrome (same gene) | Chance of having a child affected with Lynch syndrome | 50% | | Chance of having a child without Lynch syndrome | 25% |
Constitutional Mismatch repair Deficiency (CMMRD) - Occurs only when both parents have Lynch syndrome caused by a mutation in the same gene and the child inherits both mutations.
- For example, if a child inherits MSH6 mutations from both mother and father, the child would have CMMRD.
- CMMRD increases risks for many types of cancers, including childhood cancers (brain tumors, leukemia, and lymphoma) as well cancers of the colon, small intestine, urinary tract, uterus etc.
- If one person has Lynch syndrome and the genetic status of their partner is unknown, the likelihood of having a child with CMMRD is between 1 in 2856 to 1 in 11,364 depending on the gene involved (<0.1%).
Reproductive options - Conception prior to risk reducing surgeries
- Some people with lynch syndrome may choose to have children prior to risk reducing removal of the uterus/ovaries.
- No major changes
- Some people with Lynch syndrome may decide to have children and allow the children to have the option to get tested when they are 18years or older (earlier if there is a chance they are affected with CMMR-D)
- Use of Assisted Reproductive Technology
- Fertility preservation via cryopreservation:
- Cancer treatment for individuals of reproductive age may decrease their fertility
- Cryopreservation is a way for these individuals to be able to freeze their eggs or sperm for future use
- In-vitro Fertilization (IVF)
- Following cryopreservation, the egg or sperm can be used to create an embryo, which can then be implanted into the uterus
- The embryo can be implanted in the uterus of the biological mother or a surrogate
- Success rates for pregnancy : 20-35% per cycle, with the cumulative effect of three full cycles of IVF increasing these chances to 45-53%
- Cost for IVF may be a prohibitive for some families (national average total cost: $22,500-$42,000)
- Prenatal Genetic Testing (PGT)
- The IVF process can be accompanied by genetic testing called Prenatal Genetic Testing (PGT-M)
- Embryos can be implanted if they test negative for Lynch syndrome or CMMR-D
Both IVF and PGT-M are available for all individuals, including those who do not use cryopreservation.
- Using donor eggs or sperm, surrogacy
- A donor's egg or sperm can be used if the person affected with Lynch syndrome chooses to do so
- A person with Lynch syndrome may also arrange to have a surrogate carry and birth their child under a legal arrangement
- Adoption
- Some people with Lynch syndrome may choose to go through the adoption process instead of having a biological child
- Testing pregnancy for lynch syndrome is not typically recommended unless either:
- The person would elect to terminate the pregnancy based on this information
- If a child is has a 25% (1 in 4) chance to have CMMR-D
- Insurance coverage
- Health insurance are not required to cover assisted reproductive technologies, such as IVF and PGT-M
- Some may offer partial coverage
- Many reproductive clinics offer payment plans
| Presenter: Heather Nick CGCTalk: Reproductive Options and Family Planning
PRESENTATION TRANSLATED TO SPANISH: CLICK HERE
This presentation will address the following questions: - What are my chances to have a child with Lynch syndrome or CMMR-D?
- What options for family planning are there for individuals undergoing cancer treatment or prophylactic surgeries?
- What is assisted reproductive technology (ART) and how much does it cost?
- I am not interested in ART. What other options are available to me?
Inheritance of Lynch syndrome in Families:
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