The Treacher Collins syndrome is a genetic disease that affects the development of bone structure and other tissues of the facial area (Genetics Home Reference, 2016).
At a more specific level, although those affected usually present a normal or expected level of intellectual development, they present another series of alterations such as malformations in the auditory canals and in the ossicles of the ear, palpebral fissures, ocular colobomas or cleft palate, between others (Mehrotra et al., 2011).
Treacher Collins syndrome is a rare medical condition, so its incidence is estimated at approximately one case per 40,000 births, approximately (Rodrigues et al., 2015).
In addition, experimental and clinical studies have shown that most cases of Collin Treacher syndrome are due to a mutation present on chromosome 5, specifically in the 5q31.3 area (Rosa et al., 2015).
As for the diagnosis, this is usually done based on the signs and symptoms present in the affected individual, however, genetic studies are necessary to identify chromosomal abnormalities and, in addition, rule out other pathologies.
Treacher Collins Syndrome
Currently, there is no cure for Treacher Collins syndrome, usually medical specialists focus on the control of specific symptoms in each individual (National Organization for Rare Disorders, 2013).
The therapeutic interventions can include very varied specialists, in addition to different intervention protocols, pharmacological, surgical, etc. (National Organization for Rare Disorders, 2013).
Characteristics of Treacher Collins syndrome
Treacher Collins syndrome is a disorder that affects craniofacial development (OMIN, 2016; Dixon, 1996).
Specifically, the National Association of Treacher Collins Syndrome (2016), defines this medical condition as: “Alteration of development or malformation cranioencephalic genetic origin congenital, rare, disabling and without a recognized cure.”
This medical condition was initially reported in 1846 by Thompson and by Toynbee in 1987 (Coob et al., 2014).
However, it is called British ophthalmologist Edward Treacher Collins, who described it in 1900 (Mehrotra et al., 2011).
In her clinical report, Treacher Collins, she described two children who had abnormally enlarged lower eyelids, with notches and absent or poorly developed cheekbones (Chiildren’s craniofacial association, 2016).
On the other hand, the first extensive and detailed review of this pathology is performed by A. Franceschetti and D. Klein in 1949, using the term mandibulofacial disotosis (Mehrotra et al., 2011).
As we have indicated, this pathology affects the development and formation of the craniofacial structure, so that the affected individuals will present various problems, such as atypical facial features, deafness, eye alterations, digestive problems or language alterations (National Association of Syndrome Treacher Collins, 2016).
Treacher Collins syndrome is a rare disease in the general population (Genetics Home Reference, 2016).
Statistical studies indicate that it has an approximate prevalence of 1 case per 10,000-50,000 people worldwide (Genetics Home Reference, 2016).
In addition, it is a congenital pathology, so that its clinical characteristics will be present from the moment of birth (National Organization for Rare Disorders, 2013).
Regarding the distribution by sex, no recent data have been found that indicate a higher frequency in any of these. In addition, there is no distribution associated with particular geographic areas or ethnic groups (National Organization for Rare Disorders, 2013).
On the other hand, this syndrome has a nature associated with de novo mutations and hereditary patterns, therefore, if one of the parents has Treacher Collins syndrome, will present a 50% chance of transmitting this medical condition to their offspring (Chiildren’s craniofacial association, 2016).
In the cases of parents with a child with Treacher Collins syndrome, the probability of having a child with this condition is very reduced, when etiological causes are not associated with heritability factors (Chiildren’s craniofacial association, 2016)
Characteristic signs and symptoms
There are different alterations that can appear in children suffering from this syndrome, however, they are not necessarily present in all cases (Chiildren’s craniofacial association, 2016).
The genetic anomaly typical of Treacher Collins syndrome, will cause a wide variety of signs and symptoms, and in addition, all these will affect fundamentally the cranial facial development (National Organization for Rare Disorders, 2013.
- Face: the alterations that affect the facial configuration usually appear symmetrically and bilaterally, that is, on both sides of the face. Some of the most common anomalies include the absence or partial development of the cheekbones, the incomplete development of the bone structure of the lower jaw, the presence of an anusally small mandible and / or chin.
- Mouth: cleft palate, mandibular malformations, backward displacement of tongue, incomplete development and misalignment of teeth, are typical alterations in this syndrome.
- Eyes: malformation or abnormal development of the tissues surrounding the eyeballs, inclination of the eyelids, absence of lashes or very narrow lacrimal ducts. In addition, the development of slits or muscas in the tissue of the iris or the presence of abnormally small eyes is also likely .
- Respiratory tract: there are many anomalies that affect the respiratory tract, the most common are the partial development of the pharynx, narrowing or obstruction of the nostrils.
- Ears and auditory canals: malformation of auditory structures, both internal, medial, and external. Specifically, the ears may not develop or partially, accompanied by a significant narrowing of the external auditory pavilion.
- Abnormalities in the extremities: in a reduced percentage of cases, people with Treacher Collins syndrome may present alterations in their hands, specifically, the thumbs may present an incomplete to absent development.
In summary, the alterations that we can expect to appear in children suffering from Treacher Collins syndrome will affect the mouth, eyes, ears and breathing (Chiildren’s craniofacial association, 2016).
The clinical course of this medical condition will give rise to a particular neurological scheme, characterized by (Coob et al., 2014):
- Variable presence of microcephaly.
- Normal intellectual level
- Delay in the acquisition of psychomotor skills.
- Variable involvement of cognitive areas.
- Learning problems.
In some cases, the delay in the development of different areas or in the acquisition of skills is due to the presence of medical complications and / or abnormalities or physical malformations.
Secondary medical complications
Alterations in facial, auditory, buccal or ocular structure will cause a series of significant medical complications, many of which are potentially serious for the affected person (National Organization for Rare Disorders, 2013):
- Respiratory insufficiency : the reduction of the respiratory system functioning capacity is a potentially fatal medical condition for the individual.
- Infantile apnea : this medical complication supposes the presence of brief episodes of interruption of the respiratory process, especially during the phases of sleep.
- Feeding problems : anomalies in the pharynx and oral malformations will severely impede the feeding of the affected person, in many cases the use of compensatory measures will be essential.
- Loss of vision and hearing: as in previous medical complications, the abnormal development of ocular and / or auditory structures will lead to a variable affectation of both capacities.
- Delay in the acquisition and production of language : due mainly to the malformations that affect the speech device.
Of these symptoms, both the presentation / absence and severity can vary considerably among the people affected, even among members of the same family.
In some cases, the affected person may present a very subtle clinical course, so Treacher Collins syndrome may remain undiagnosed. In other cases, serious anomalies and medical complications may appear that put the survival of the individual at risk (National Organization for Rare Disorders, 2013).
As we have indicated previously, the Treacher Collins syndrome has a genetic nature of congenital type, therefore, the affected people will present this medical condition from birth.
Specifically, most of the cases are associated with the presence of abnormalities on chromosome 5, in the 5q31 area. (Rosa et al., 2015).
In addition, different investigations throughout the history of this syndrome have indicated that it may be due to specific mutations in the TCOF1, POLR1C or POLR1D genes (Genetics Home Reference, 2016).
Thus, the TCOF1 gene is the most frequent cause of this pathology, representing approximately 81-93% of the total cases. On the other hand, the POLR1C and POLRD1 genes give rise to approximately 2% of the rest of the cases (Genetics Home Reference, 2016).
This set of genes seems to have a significant role in the development of bone, muscle and skin structure of the facial areas (Genetics Home Reference, 2016).
Although most cases of Treacher Collins syndrome are sporadic, this pathology presents a heritability pattern of parents to children of 50%.
The diagnosis of Treacher Collis syndrome is based on clinical and radiological findings and, in addition, several complementary genetic tests are used (Genetics Home Reference, 2016).
In the case of clinical diagnosis, a detailed physical and neurological examination is carried out in order to specify them. Normally, this process is carried out based on the diagnostic criteria of the disease.
One of the most used tests in this evaluation phase, are X-rays, they are able to offer information about the presence / absence of craniofacial malformations (National Organization for Rare Disorders, 2013).
Although certain facial features are observable directly, X-rays give precise and accurate information about the development of the maxillary bones , the development of the skull, or the development of additional malformations (National Organization for Rare Disorders, 2013).
In addition, in cases in which the physical signs are still very subtle or in which it is necessary to confirm the diagnosis, various genetic tests can be used to confirm the presence of mutations in the TCOF1, POLR1C and POLR1D genes (National Organization for Rare Disorders , 2013).
In addition, when there is a family history of Treacher Collins syndrome, it is possible to perform a prenatal diagnosis. Through amniocentesis we can examine the genetic material of the embryo.
Currently there is no type of curative treatment for Treacher Collins syndrome, so experts focus on the treatment of the most common signs and symptoms.
In this way, after the initial confirmation of the pathology, it is essential that an evaluation of the possible medical complications be made (Huston Katsanis & Wang Jabs, 2004):
- Alterations of the pathways areas
- Serious alterations of the facial structure.
- Mouth slits.
- Alterations of swallowing.
- Additive alterations.
- Eye and visual problems.
- Dental anomalies.
The realization of all these anomalies is fundamental for the design of an individualized treatment and adjusted to the needs of the affected person .
Thus, the management of this individualized treatment usually requires the presence of professionals from different areas such as pediatricians, plastic surgeons , odontologists, audiologists, speech therapists, psychologists, etc. (Huston Katsanis & Wang Jabs, 2004).
Specifically, all medical complications are divided into several temporal phases to address their medical therapeutic intervention (Huston Katsanis & Wang Jabs, 2004):
- From 0 to 2 years old : treatment of alterations in the respiratory tract and resolution of feeding problems
- From 3 to 12 years old : treatment of language disorders and integration in the education system
- From 13 to 18 years old : use of surgery for the correction of cranio-facial malformations.
In all these phases, both the use of drugs and quriric reconstruction are the most common therapeutic techniques (National Organization for Rare Disorders, 2013).