Treacher Collins syndrome

Treacher Collins syndrome
Synonyms	Treacher Collins–Franceschetti syndrome, mandibulofacial dysostosis, Franceschetti-Zwalen-Klein syndrome
Pronounce
Field	Medical genetics
Symptoms	Deformities of the ears, eyes, cheekbones, chin
Complications	Breathing problems, problems seeing, hearing loss
Onset
Duration
Types
Causes	Genetic
Risks
Diagnosis	Based on symptoms, X-rays, genetic testing
Differential diagnosis	Nager syndrome, Miller syndrome, hemifacial microsomia
Prevention
Treatment	Reconstructive surgery, hearing aids, speech therapy
Medication
Prognosis	Generally normal life expectancy
Frequency	1 in 50,000 people
Deaths

Treacher Collins syndrome (TCS), also known as mandibulofacial dysostosis, is a rare genetic condition marked by craniofacial deformities. The severity and exact nature of these deformities can vary widely among individuals, ranging from mild to severe. Despite the physical manifestations, individuals with TCS typically have normal intelligence.

Genetics and Pathogenesis

TCS is primarily caused by mutations in the TCOF1, POLR1C, or POLR1D genes. These genes play crucial roles in early craniofacial development. Most cases of TCS are inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. However, a considerable percentage of cases result from new mutations in the gene and occur in people with no history of the disorder in their family.

Clinical Features

The characteristic features of TCS include abnormalities of the ears, eyes, cheekbones, and chin. Patients may present with downward-slanting palpebral fissures, colobomas of the lower eyelids with a paucity of eyelashes medial to the defect, and hypoplasia of the facial bones (especially the zygomatic complex and mandible).

A significant number of individuals with TCS also have a cleft palate and may experience hearing loss due to malformations of the outer and middle ear. Breathing difficulties and problems with vision may occur due to the anatomical abnormalities.

Management and Prognosis

Management of TCS is symptomatic and requires a multidisciplinary approach. Reconstructive surgery may be necessary to address the craniofacial abnormalities, and hearing aids or cochlear implants may be used to manage hearing loss. Regular monitoring for potential breathing and feeding problems, particularly in infancy, is critical.

The long-term prognosis for individuals with TCS is generally favorable. The condition does not typically affect intelligence or lifespan, and most individuals with TCS lead fulfilling lives with proper management.

References

• Genetics Home Reference: Treacher Collins Syndrome
• National Organization for Rare Disorders: Treacher Collins Syndrome
• PubMed: Treacher Collins syndrome: clinical features, genetic etiology, and potential therapeutic directions

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