Treacher Collins syndrome
Treacher Collins syndrome
Treacher Collins syndrome is a genetic disorder that affects growth and development of the head. It prevents the skull, cheek and jawbones from developing properly, causing facial anomalies and hearing loss. About one child in every 50,000 is affected. Problems range in severity from mild to very severe. In most cases, the child’s intelligence is unaffected.
Treacher Collins syndrome is either inherited or caused by a new change in a gene at the time of conception. There is no cure, but skull and face (craniofacial) surgery can improve speech and reduce some of the more severe craniofacial anomalies.
Treacher Collins syndrome is also known as mandibulofacial dysostosis or Franceschetti syndrome.
Symptoms of Treacher Collins syndrome
Symptoms and signs range from barely noticeable to severe and disabling. Typically, the characteristics of a person with Treacher Collins syndrome may include:
cleft palate
small jawbone (micrognathia)
disproportionately large mouth (macrostomia)
small or absent cheekbones
large and pointed nose
droopy misshaped eyes with notched lower lids
absent lower eyelashes
absent floor of the eye sockets
overgrowth of scalp hair onto the cheeks
low-set, misshapen, small or absent ears
deformities of the ear canal
conductive hearing loss or conductive deafness, caused by malformations of inner ear structures.
Cause of Treacher Collins syndrome
A change in the gene
TCOF1
causes up to 93 per cent of cases of Treacher Collins syndrome. This gene, located on chromosome 5, is responsible for facial development.
In about half of all cases,
TCOF1
spontaneously changes at conception but what triggers the gene change is unknown. In other cases, Treacher Collins syndrome caused by the altered
TCOF1
gene is inherited as an autosomal dominant trait. This means that the child inherits the affected gene from a parent with Treacher Collins syndrome, and an unaffected copy of the gene from their other parent.
Another two per cent of cases are thought to be caused by changes in the
POLR1C
and
POLR1D
genes.
Exactly how the gene changes cause facial anomalies is not known. They are thought to cause cell death (apoptosis) of facial bone, cartilage and soft tissue during weeks three to eight of fetal development.
Pattern of inheritance of Treacher Collins syndrome
An affected parent has a 50 per cent chance (one in two) of passing the affected gene on to each child they have. This is a chance event and cannot be altered. The severity of facial anomalies in a child who inherits the altered gene cannot be predicted.
Complications of Treacher Collins syndrome
Complications depend on the severity of the condition. Treacher Collins syndrome may lead to complications including:
feeding problems
– a cleft palate prevents the baby from suckling and swallowing
breathing problems
– a small jaw and average-sized tongue can interfere with breathing and lead to sleep apnoea. A tracheostomy (surgical opening in the windpipe) may be needed in severe cases
speech problems
– may be caused by a cleft palate, conductive hearing loss or both
learning problems
– may be caused by hearing loss or deafness. Treacher Collins syndrome generally does not affect a child’s intelligence
dry eye syndrome
– may occur when there are not enough tears to keep the eyes moist and comfortable. Complications of dry eye syndrome include recurrent eye infections
psychological problems
– may include low self-esteem and depression caused by social stigma.
Diagnosis of Treacher Collins syndrome
Tests used to diagnose Treacher Collins syndrome may include:
physical examination
medical history
genetic testing – this is often not necessary as the diagnosis can be made based on clinical features alone.
Treatment for Treacher Collins syndrome
Treatment depends on the severity of the condition, but may include:
genetic counselling
– for the individual or the whole family, depending on whether the condition was inherited or not
hearing aids
– usually helpful in the case of conductive hearing loss
dental work
– including orthodontic work to help correct the child’s bite
speech therapy
– to improve the child’s communication skills. Speech pathologists also work with people who have trouble swallowing food or drink
surgery
– a number of operations are available that can improve function and appearance.
Surgery for Treacher Collins syndrome
Depending on the severity of the craniofacial anomalies, surgical options may include:
reconstruction of lower eyelids
closure of cleft palate
repair of absent facial bones including cheekbone and lower eye socket
ear reconstruction
re-positioning of the lower jaw (orthognathic surgery)
rhinoplasty to improve the look of the nose.
The timing of these operations depends on the child’s age and stage of development. For example, eye surgery may be performed during infancy, ear reconstruction between the ages of five and seven years, and facial surgery after adolescence when the face has stopped growing. Generally, reconstructive surgery has good results and helps the person to have a good quality of life.
Genetic counselling and Treacher Collins syndrome
If your child has been diagnosed with Treacher Collins syndrome, or if it runs in your family, it may be helpful to speak to a genetic counsellor.
Genetic counsellors are health professionals qualified in both counselling and genetics. As well as providing emotional support, they can help you to understand Treacher Collins syndrome and what causes it, how it is inherited, and what a diagnosis means for your child’s health and development, and for your family. Genetic counsellors are trained to provide information and support that is sensitive to your family circumstances, culture and beliefs.
If Treacher Collins syndrome runs in your family, a genetic counsellor can explain what genetic testing options are available to you and other family members. You may choose to visit a genetic counsellor if you are planning a family – to find out your risk of passing the condition on to your child, or to arrange for prenatal tests.
The
Genetic Support Network of Victoria
(GSNV)
External Link
is connected with a wide range of support groups throughout Victoria and Australia and can connect you with other individuals and families affected by Treacher Collins syndrome.
Where to get help
Your
GP (doctor)
Paediatrician
Dentist
Orthodontist
Craniofacial (skull and face) surgeon
Genetic counselling services
– available at most large public maternity hospitals
Speech Pathology
Australia
External Link
Tel.
(03) 9642 4899
, or Tel.
1300 368 835
outside Victoria
Victorian Clinical Genetics Services
(VCGS)
External Link
, Royal Children’s Hospital Tel.
1300 118 247
Genetic Support Network
Victoria
External Link
Tel.
(03) 8341 6315
Murdoch Children’s Research
Institute
External Link
Tel.
(03) 8341 6200