Bardet Biedl Syndrome (BBS) Genetics
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- Опубликовано: 22 июл 2024
- 2021 BBSFA Virtual Conference Series
The Bardet Biedl Syndrome Foundation & Family Association is proud to present, BBS Genetics, the second in a new series of informational videos about BBS.
Bardet Biedl Syndrome Foundation Website: www.bardetbiedl.org
CRIBBS Registry: www.bbs-registry.org
Questions? Contact Alexis Jones at alexis@bardetbiedl.org
Thank you to human genetics researcher Erica Davis, Ph.D. at Lurie's Children's Hospital of Chicago & Northwestern University for presenting.
Thank you for that explanation!
What does conflicting mean on a genetic test results vs not applicable ?
Can I get more information? Also where should we go for help with this? My son has this marked on DNA as well as SLS7.
Hi Carol, please email alexis@bardetbiedl.org and we'd be happy to connect and provide you with more resources.
If one parent Carries BBS7 and one Carries BBS10 and their child shows BBS7 & 10 on genetic test with one variant in each are they carriers or do they have BBS ?
"The basic answer is that the child is a carrier of 2 different BBS genes, but that does not mean that they have BBS. As far as we know, to be a carrier of two different BBS genes is not enough to cause the condition. The syndrome comes when a person has DNA variants (or changes) in both copies of a single particular BBS gene.
That being said, there are common, uncommon, and unique DNA variants of each BBS gene. In a standard genetic test, the report will list whether the person has a DNA variant in a BBS gene that is known to cause the syndrome (“pathogenic" or "likely pathogenic"). You may also see that a person has a VUS or "variant of unknown significance" in a particular gene. This means that the copy of the gene is not what is known to be the normal version of that gene, but the DNA variant has not been proven to cause BBS. Unfortunately many genetic counselors sometimes will inform a patient or family that they "only have one copy" of a BBS gene and ignore a finding that the other copy is a "VUS".
So to fully answer the question, you would need to confirm with the genetic counselor that the person in question has a "normal" copy of the BBS7 and BBS10 genes. If so, then the child is a carrier and does not have a genetic diagnosis of BBS with that information. If they do have a known BBS10 mutation and a VUS in the other copy of the gene, further specialized testing would be required to determine if that other mutation causes the syndrome. If the child has the clinical criteria for a BBS diagnosis, and the genetic test indicates carrier for each of BBS7 and BBS10, one other possibility could be that other causal DNA variant was not detected in this clinical test and should be referred to a genetics research study."