Treacher-collins syndrome

Inheritance

How is Treacher Collins syndrome inherited?

About 60% of those with Treacher Collins syndrome (TCS) are the first in their family to have this condition due to a new/sporadic (de novo) genetic change. If it is new to the family and the parents are not affected the chance for them to have another child with TCS is small. However, parents should be thoroughly evaluated because some people have such mild features they are not diagnosed and in one of the genes that causes TCS parents may be unaffected carriers.

Most cases of TCS are caused by mutations or disease causing changes in the TCOF1 gene. Mutations in TCOF1 gene are inherited in an autosomal dominant manner. This means that if a parent has a mutation in this gene, they have a 1 in 2 or 50% chance to pass on this condition to each of their children, regardless of whether it is a boy or girl. This also means that there is a 50% chance that a parent with TCS would not pass this condition to their children. POLR1D and POLR1C are two genes that are implicated in a minority of cases of TCS. Like TCOF1, mutations in POLR1D gene are inherited in an autosomal dominant manner.

In some families, TCS is inherited in an autosomal recessive pattern due to mutations in POLR1C. A person with a genetic change in both copies of their POLR1C gene will have TCS. Each parent passes on one genetic change in this gene and is a carrier of TCS. Carriers of a condition usually don't have medical problems, but if they have children with another carrier of a change in the POLR1C gene, they have a 1 in 4 or 25% chance of having a child with the condition.

To learn more about the geneics of Treacher Collins syndrome, speak with a geneticist or genetic counselor. You can find a genetics clinic near you by searching the American College of Medical Genetics. To find a genetic counselor search on the National Society of Genetic Counselors under "Find a Counselor".

References
  • Treacher Collins Syndrome - NORD (National Organization for Rare Disorders). (2013). Retrieved February 29, 2016, from http://rarediseases.org/rare-diseases/treacher-collins-syndrome/
  • Katsanis SH, Jabs EW. Treacher Collins Syndrome. 2004 Jul 20 [Updated 2012 Aug 30]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. Available from: http://www.ncbi.nlm.nih.gov/books/NBK1532/
Show More Content Like This

More Inheritance Content

What does it mean to have a "variant" or "variant of unknown significance" in the gene for Treacher Collins syndrome (TCS)?

What does it mean to have a "variant" or "variant of unknown significance" in the gene for Treacher Collins syndrome (TCS)?

The main gene that causes Treacher Collins syndrome (TCS) has been found to have many different changes that cause TCS. Most families have a different change than any of the other families who have TCS.

A "variant" is another word for a change in a gene. Variants can be benign (not disease causing), pathogenic (disease causing), or of unknown clinical significance (undetermined). Looking at a person's genetic testing report can be helpful to know what type of variant or genetic change was identified.

If a variant has not been seen in another family previously, and they are not sure how the change affects the protein that is supposed to be built from the gene code, the variant may be called a "variant of unknown significance". This means there is a change, but they do not know if it causes TCS.

With additional information from research and more people getting genetic testing, variants may be become reclassified as disease causing or as benign. In some cases, testing other people in the family may provide additional evidence about whether a variant could potentially cause TCS. A person with a variant should periodically check with their doctor to determine if the interpretation of a variant has changed.

A genetic counselor or geneticist can help to interpret gene testing results. You can find a genetics clinic near you by searching the American College of Medical Genetics. To find a genetic counselor search on the National Society of Genetic Counselors under "Find a Counselor".

References
  • Treacher Collins Syndrome - NORD (National Organization for Rare Disorders). (2013). Retrieved February 29, 2016, from http://rarediseases.org/rare-diseases/treacher-collins-syndrome/
  • Katsanis SH, Jabs EW. Treacher Collins Syndrome. 2004 Jul 20 [Updated 2012 Aug 30]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. Available from: http://www.ncbi.nlm.nih.gov/books/NBK1532/

We use cookies to ensure that we give you the best experience on our website. By continuing to browse this site, you are agreeing to our use of cookies.

Continue Find out more about our use of cookies and similar technology

This content comes from a hidden element on this page.

The inline option preserves bound JavaScript events and changes, and it puts the content back where it came from when it is closed.

Remember Me