Research Summary

Family Communication and Cascade Testing for Fragile X Syndrome

Date Published: June 2018

What was the research about?

Because fragile X syndrome (FXS) is an inherited condition, it often affects multiple members of both immediate and extended families. Our Fragile X World researchers wanted to learn more about how families communicate about FXS and what factors play a role in the decision to test other children and extended family members after the initial diagnosis.

What did the research team do?

We conducted a survey which asked parents:

  • How they found out FXS was in their family
  • How many of their children and extended family members had been tested
  • How they communicated about FXS with their children and with other family members

Who was in the study?

A total of 679 caregivers of one or more children with FXS took part in the survey. Most caregivers who took the survey were white, college educated, married women. Their children ranged in age from toddlers to adults.

1,117 children were included in the survey

Gender of children included in the survey

Pie chart displaying the percent distribution of children included in the study by gender. 72% male, 28% female.
  72% Male
  28% Female

FXS status of children included in the survey

Full mutation
69%
Premutation
4%
No FXS
13%
Not tested
14%

What did the research team learn?

Learning about FXS in the family

Most parents found out about fragile X when one of their children was diagnosed. These families did not know that fragile X was in their family beforehand. Of those who did know that fragile X was in their family, only half knew they were carriers. Younger parents (40 and under) were more likely to know they were carriers before one of their children was diagnosed.

Parents' knowledge of FXS in their family

Pie chart displaying the percent distribution of parents' knowledge of FXS in their family. 90% did not know FXS was in their family, 5% knew FXS was in their family but did not know they were a carrier, and 5% knew they were a carrier.
  90% Did not know FXS was in their family
  5% Knew FXS was in their family but did not know they were a carrier
  5% Knew they were a carrier
FXS testing for family members

Most families had tested all their children. Those with children who had not been tested listed reasons such as: the child did not show signs of FXS, the test is expensive, they didn't want to know yet, or they planned to test in the future. However, about a third of these families said they do not plan to test their child. One or more extended family members had been tested in most families.

Children tested for FXS

Pie chart displaying the percentage of children families had tested for fragile X syndrome. 84% tested all of their children, 16% tested some of their children.
  84% All
  16% Some

Extended family tested for FXS

Pie chart displaying the percentage of extended families tested for fragile X syndrome. 55% had some extended family members who were tested, 28% had no extended family members who were tested, and 17% had all extended family members who were tested.
  17% All
  55% Some
  28% None
Communication with children and extended family members

About two-thirds of all the children who had been tested for fragile X had been told the results of the testing, and most families (79%) talked with their children about FXS at least occasionally. Parents did not tell results to one-third of all the children tested. This was especially true for children who were male or those with the premutation. The most common reason for not telling, especially for parents of adolescents/adults, was that the child would not understand the result. Some parents planned to tell the results to younger children when they were old enough to understand. Most families talked with relatives about FXS occasionally or a lot.

What does this mean for families?

These findings confirm the importance of effective communication between family members following the first FXS diagnosis. Once a child is diagnosed, the family must decide when and how to communicate information about fragile X to their children as well as to their extended family members. In addition, decisions about testing other children must be made.

Families may need information about family planning options, such as preimplantation genetic testing or adoption, and the benefits and risks associated with them. Parents can use this information to inform their own decisions as well as those of their extended family members.

Genetic counselors can help to ensure that families are well informed about how fragile X is inherited and have materials to share with extended family members about how to get tested. Genetic counselors may also help individuals draft letters to share information about fragile X with family members and assist with identifying a "trusted source" within the family who could mediate the delivery of the fragile X test results.

If you want to learn more about the genetics and inheritance of fragile X, or if you are planning to share information about fragile X with your child or extended family, a genetic counselor can be a good source of information, guidance, and support.

Related resources

The National Fragile X Foundation (NFXF) is a great resource for all things related to fragile X. Their website provides information about the genetics and inheritance of fragile X and how common it is in the population.

For more information about how to talk to your child about fragile X, please visit the NFXF website to read about helpful tips and strategies.

To learn more about genetic counselors and how they can help, please visit the National Society of Genetic Counselors or the Centers for Disease Control and Prevention.

To find a genetic counselor in your area:

Read the full article by Melissa Raspa and colleagues


Source. Raspa, M., Edwards, A., Wheeler, A.C. et al. Journal of Genetic Counseling (2016) 25: 1075.