Treacher Collins Syndrome: 10 Interesting Facts

Treacher Collins Syndrome is primarily caused by mutations in the TCOF1, POLR1D, and POLR1C genes. These mutations disrupt the normal development of craniofacial tissues during embryonic growth.¹, ²

The proteins produced by these genes play an important role in the early development of bone and other tissues of the face. They are responsible for the formation and functioning of certain cell structures, including the ribosomes. "A ribosome is an intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell."³

Impaired ribosome biogenesis leads to reduced cell proliferation, which affects the development of facial structures, such as the cheekbones, jaw, and ears.

The most prominent symptom of Collins-Franceschetti Syndrome is craniofacial anomalies.

Individuals with this condition typically have the following clinical features:

• Down-slanting eyes
• Coloboma. The most common colobomas develop in the iris causing the pupil to have a keyhole or cat-eye shape
• Underdeveloped cheekbones
• Small jaw
• Cleft palate or high-arched palate
• Malformed or absent ears.

These physical features can vary in severity, and some individuals may also experience:

• Hearing loss
• Breathing problems
• Dental problems.⁴

In some cases, the disorder may affect other parts of the body, such as the limbs or organs.

Treacher Collins Syndrome is a complex disorder that requires a multidisciplinary approach to treatment.¹, ⁶

1. Medical interventions aim to address the specific symptoms and complications faced by affected individuals.
2. Surgery plays a significant role in correcting craniofacial abnormalities, reconstructing the ears, and improving breathing and swallowing functions.⁵
3. Speech therapy, hearing aids, and dental interventions are often employed to enhance communication skills and improve overall quality of life.
4. Psychological support and counseling are also crucial for individuals and families coping with the emotional and social challenges associated with the syndrome, including low self-esteem.

Disrupted craniofacial development in utero may result in small or underdeveloped external ears, called microtia. The small or misshapen external ears are often low-set and in some babies, the ear canal may also be narrow or missing. This is called anotia.⁴

In these cases, the natural conduction of sound through the air-filled ear canal and middle ear may be affected, resulting in a conductive hearing loss. An ear canal which is too narrow or non-existent will preclude the fitting of a conventional hearing device to overcome the hearing loss.

Thankfully, all hope is not lost. A bone-anchored hearing aid or BAHA may be fitted instead. This allows sound to be conducted via the bones of the skull, bypassing the outer and middle ear completely. 

A BAHA consists of three parts:

1. A titanium implant: This is surgically implanted into the skull bone behind the ear.
2. An external abutment: Connects to the titanium implant and transfers sound from the processor into mechanical vibrations.
3. A sound processor: A detachable device which captures sounds via the microphone and converts them into vibrations.

1. Life Expectancy: Treacher Collins Syndrome typically does not affect life expectancy unless severe respiratory or feeding problems arise.
2. Intelligence: Intelligence is not directly affected by the syndrome, as it primarily impacts physical development and functionality.
3. Prevalence: Treacher Collins Syndrome is a rare disorder, occurring in approximately 1 in 50,000 births.
4. Genetic Basis: The syndrome is inherited in an autosomal dominant manner, where one copy of the altered gene in each cell may cause the disorder. In some cases, it may result from spontaneous gene mutations.
5. Prenatal Detection: Through advanced medical imaging techniques like ultrasound and genetic testing, Treacher Collins Syndrome can be detected before birth.
6. Severity Varies: The severity of symptoms can vary widely among individuals, ranging from mild facial abnormalities to more extensive craniofacial deformities.
7. Hearing Loss: Conductive hearing loss is a common complication due to underdeveloped or absent middle ear structures in individuals with Treacher Collins Syndrome.
8. Dental Issues: Dental abnormalities, such as misaligned teeth and missing or malformed teeth, are prevalent in individuals with this syndrome.
9. Early Intervention: Early intervention, including surgical and therapeutic interventions, can significantly improve the quality of life for individuals with Treacher Collins Syndrome.
10. Support Networks: Various organizations and support groups exist worldwide to provide resources, information, and emotional support to individuals and families affected by the syndrome.⁶

• Franceschetti-Zwahlen-Klein syndrome
• Mandibulofacial dysostosis (MFD1)
• Treacher Collins-Franceschetti syndrome
• Zygoauromandibular dysplasia

In conclusion, Treacher Collins Syndrome, or Franceschetti syndrome, is a rare congenital disorder characterized by facial abnormalities and associated complications. While the physical symptoms of the condition can pose significant challenges, early intervention, multidisciplinary treatments, and emotional support can greatly improve the quality of life for affected individuals.

With ongoing research and support, we continue to enhance our understanding of this enigmatic syndrome and work toward better treatments and outcomes for those living with Treacher Collins Syndrome.

1. Trainor P., Dixon J., Dixon M. (2009). Treacher Collins syndrome: etiology, pathogenesis and prevention. Eur J Hum Genet.;17(3):275-283.
2. Dauwerse J., Dixon J., Seland S., et al. (2011). Mutations in genes encoding subunits of RNA polymerases I and III cause Treacher Collins syndrome. Nat Genet.;43(1):20-22.
3. Ribosome. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute. Retrieved from https://www.genome.gov/genetics-glossary/Ribosomeellular,that%20fold%20to%20form%20proteins. on 19 June 2023.
4. Canfield MA, Langlois PH, Nguyen LM, Scheuerle AE. (2009). Epidemiologic features and clinical subgroups of anotia/microtia in Texas. Birth Defects Research (Part A): Clinical and Molecular Teratology, 85:905-913.
5. Posnick J. (2014). Treacher Collins Syndrome. Plast Reconstr Surg.;133(3):471e-480e.
6. Geirdal A., Saltnes S., Storhaug K., Åsten P., Nordgarden H., Jensen J. (2015). Living with orofacial conditions: psychological distress and quality of life in adults affected with Treacher Collins syndrome, cherubism, or oligodontia/ectodermal dysplasia-a comparative study. Qual Life Res. Apr;24(4):927-35. doi: 10.1007/s11136-014-0826-1. Epub 2014 Oct 25. Erratum in: Qual Life Res. 2015 Jul;24(7):1795. PMID: 25344415; PMCID: PMC4366539.

_{The information contained in this article is for educational and informational purposes only. You should not use the information as a substitute for, nor should it replace, professional medical advice. If you have any questions about your health, you should always consult with a physician or other health-care professional.}