Treacher Collins syndrome
Introduction to Treacher Collins Syndrome
Treacher Collins syndrome (TCS) is a rare genetic disorder characterized by craniofacial deformities. It affects the development of bones and tissues of the face, particularly the cheekbones, jaws, ears, and eyelids. TCS is caused by mutations in genes involved in the development of the first and second pharyngeal arches during embryonic development.
Key points:
- Incidence: Approximately 1 in 50,000 live births
- Inheritance: Autosomal dominant (70% due to new mutations)
- Primary genes involved: TCOF1 (78-93% of cases), POLR1C, and POLR1D
- Severity: Highly variable, even within families
Clinical Features of Treacher Collins Syndrome
The clinical presentation of TCS can vary widely, but typical features include:
- Craniofacial abnormalities:
- Downward-slanting palpebral fissures
- Coloboma of the lower eyelid
- Malar hypoplasia (underdeveloped cheekbones)
- Micrognathia (small lower jaw)
- Cleft palate (in about 30% of cases)
- Ear anomalies:
- Microtia or anotia (small or absent external ears)
- Atresia of external auditory canals
- Conductive hearing loss (in up to 90% of cases)
- Airway issues:
- Choanal atresia or stenosis
- Narrowed nasopharynx
- Potential for obstructive sleep apnea
- Other features:
- Normal intelligence in most cases
- Possible feeding difficulties in infancy
- Occasional cardiac or renal anomalies
Diagnosis of Treacher Collins Syndrome
Diagnosis of TCS is primarily based on clinical findings and can be confirmed through genetic testing:
- Clinical diagnosis:
- Physical examination focusing on craniofacial features
- Audiological evaluation
- Ophthalmological assessment
- Imaging studies:
- CT or MRI scans to assess craniofacial structures
- X-rays to evaluate jaw and facial bone development
- Genetic testing:
- Molecular genetic testing for TCOF1, POLR1C, and POLR1D mutations
- Prenatal diagnosis possible through chorionic villus sampling or amniocentesis
- Differential diagnosis:
- Nager syndrome
- Miller syndrome
- Goldenhar syndrome
Management of Treacher Collins Syndrome
Management of TCS requires a multidisciplinary approach and is primarily supportive:
- Neonatal period:
- Airway management (may require tracheostomy in severe cases)
- Feeding support (nasogastric tube or gastrostomy if necessary)
- Hearing management:
- Early hearing aids or bone-anchored hearing devices
- Speech and language therapy
- Ophthalmological care:
- Treatment of exposure keratitis
- Correction of colobomas
- Surgical interventions (timing varies):
- Cleft palate repair (6-12 months of age)
- Orbital reconstruction (5-7 years)
- Mandibular distraction osteogenesis for severe micrognathia
- Ear reconstruction (typically after age 6)
- Psychosocial support:
- Counseling for patients and families
- Support groups and resources
Prognosis of Treacher Collins Syndrome
The prognosis for individuals with TCS is generally good with appropriate management:
- Life expectancy is typically normal
- Cognitive development is usually unaffected
- Quality of life can be significantly improved with early intervention and comprehensive care
- Ongoing medical and surgical management may be required throughout life
- Psychosocial challenges may persist, requiring continued support
Long-term follow-up is essential to address evolving needs and complications.
