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".
Other Questions About Treacher-collins syndrome
- Who else in my family should be tested for Treacher Collins syndrome (TCS)?
- What type of psychological/ adjustment issues can those with Treacher Collins syndrome (TCS) face?
- What is Treacher Collins syndrome?
- What is the usual abbreviation for Treacher Collins syndrome?
- What is the life expectancy in Treacher Collins syndrome (TCS)?
