|Year : 2020 | Volume
| Issue : 3 | Page : 145-148
Plausible occupational impact on familial Treacher–Collins syndrome: Dental findings and management
Namita Kalra, Rishi Tyagi, Amit Khatri, Puja Sabherwal, Padma Yangdol
Department of Pedodontics and Preventive Dentistry, Guru Teg Bahadur Hospital, University College of Medical Sciences, Delhi, India
|Date of Submission||11-Mar-2020|
|Date of Decision||18-May-2020|
|Date of Acceptance||21-May-2020|
|Date of Web Publication||14-Aug-2020|
Department of Pedodontics and Preventive Dentistry, Guru Teg Bahadur Hospital, University College of Medical Sciences, Delhi
Source of Support: None, Conflict of Interest: None
Treacher–Collins syndrome (TCS) is a disorder of autosomal dominant inheritance commonly linked to the mutation of human gene TREACLE (Treacher–Collins–Franceschetti 1). It primarily affects the structures derived from the first and second brachial arches by leading to neuroepithelial cell apoptosis and failure of neural crest cell migration. TCS commonly presents with anomalies of zygoma, mandible, and ears with typical bird-like facies. The variation in severity is found to increase over generations and is affected by environmental factors and stochastic events. The paper presents a case of familial TCS in a mother and daughter with increased severity in the second generation; it also illustrates the correlation of occupational impact due to cumulative maternal exposure to polyvinyl acetate-based adhesive resin as an occupational hazard for over 30 years.
Keywords: Dental manifestations, familial Treacher–Collins syndrome, occupational impact
|How to cite this article:|
Kalra N, Tyagi R, Khatri A, Sabherwal P, Yangdol P. Plausible occupational impact on familial Treacher–Collins syndrome: Dental findings and management. Indian J Dent Sci 2020;12:145-8
|How to cite this URL:|
Kalra N, Tyagi R, Khatri A, Sabherwal P, Yangdol P. Plausible occupational impact on familial Treacher–Collins syndrome: Dental findings and management. Indian J Dent Sci [serial online] 2020 [cited 2020 Sep 23];12:145-8. Available from: http://www.ijds.in/text.asp?2020/12/3/145/292275
| Introduction|| |
Treacher–Collins syndrome (TCS) (OMIM-154500) also known as Treacher–Collins–Franceschetti syndrome or mandibulofacial dysostosis was first termed by Thompson in 1846, described originally by Dr. Treacher Collins in 1900 and elaborately described by Franceschetti and Klein in 1949. The incidence is 1 in 50,000 live births., Clinically, it is characterized by hypoplasia of structures of first and second brachial arches: zygoma, mandible, and external ear. It is characterized by downward slanting palpebral fissures with colobomas of lower eyelids, total or partial absence of lower eyelashes, blind pits between the mandibular angle and tragus, and hearing loss. Systemic manifestations include malformations of kidneys, heart, vertebral column, and extremities. Oral findings include cleft lip with or without cleft palate, malocclusions, and enamel hypoplasia. TCS exhibits autosomal dominant inheritance with variability in penetrance, linked to human gene 5q 31.3–32 locus linked commonly to the mutated gene Treacle (Treacher–Collins–Franceschetti 1 [TCOF1]). Collectively, the variable severity indicates that genetic background, environmental factors, and stochastic events contribute to the clinical variation observed in TCS patients.
We present a case of familial incidence of TCS in a mother and her 8-year-old daughter with possible increase in the severity of symptoms over generations and plausible association of vinyl acetate-based adhesive (occupational exposure to mother for 33 years) with increased disease severity.
| Case Report|| |
The 8-year-old girl reported to the Department of Pedodontics and Preventive Dentistry, UCMS and GTB Hospital, Delhi, with the chief complaint of multiple decayed teeth and pain in the lower right back tooth region since 1 month. The patient's mother had a complaint of feeding problems since birth and nasal regurgitation with the presence of cleft lip and palate, which was repaired surgically at 1–2 years of age. The growth and developmental milestones were described as normal as per the chart developed by the Institute for Human Services for the Ohio Child Welfare Training Program (2007).
Extraoral examination of the patient revealed the following findings: downward slanting palpebral fissures, colobomas of lower eyelids in both eyes, sparse eyelashes of lower eyelids, and hypoplasia of the malar region. Examination also revealed the presence of bony enlargement on the right wrist region, which was confirmed by fine-needle aspiration cytology to be ganglion cyst of the bone [Figure 1]. Intraoral findings revealed narrow U-shaped and V-shaped arches in the maxilla and mandible, respectively. Orthopantomogram revealed the following: rotation, 51, 52; grossly carious with root resorption, 74, 75, 84; Class I caries, 85, 55, 64, 65 [Figure 2].
|Figure 1: (a) Extraoral view (top left), (b) profile view (top right), (c) ganglion bone cyst on flexor aspect of right wrist (bottom)|
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|Figure 2: (a) Buccal view (top left), (b) maxillary occlusal view (top right), (c) mandibular occlusal view (bottom left), (d) orthopantomogram (bottom right)|
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Detailed family history revealed that the mother was also affected with typical TCS phenotype with downward slanting palpebral fissures, ear anomalies, and hypoplasia of the malar bones and mandible along with an interesting presentation of scrotal tongue with no other intraoral findings [Figure 3]. The four siblings all older to the patient in question were unaffected. No other maternal or paternal relatives were affected [Line Diagram 1]. The age of the mother at conception was 37 years. She was also working from home as a “bindi maker” with “vinyl acetate-” based adhesive since the age of 12 years with cumulative exposure time of 33 years.
|Figure 3: Mother's frontal view (left), profile view (mid), intraoral view of the tongue (right)|
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Based on clinical and radiographic findings, the diagnosis of TCS with familial incidence was made. During the first visit, preventive care was initiated with delivery of oral hygiene instructions and demonstration of brushing technique. Diet history was taken and dietary counseling was done. During the second visit to allay apprehension of the child, a tour of the dental clinic was given and the tell-play-do technique was used to demonstrate restorative equipment with restoration of 85, 55 using glass ionomer cement (GlasIonomer FX ULTRA, SHOFU). At the third visit, restorations were completed. At the fourth and fifth visits, extractions were done [Figure 4] using hypnotic technique for relaxation by operator having diploma in hypnotherapy affiliated to the American Hypnosis Association. Due to economic factors, the patient's father did not want to undergo the burden of orthodontic intervention.
|Figure 4: Top, postoperative maxillary occlusal view; bottom, postoperative mandibular occlusal view|
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The patient was referred to the department of ear, nose, and throat for workup of hearing or speech assessment, which revealed mild conductive deafness of the right ear and mild speech impairment. Speech therapy was initiated for the patient. Regular follow-up visits were held monthly, which leads to improved confidence and better academic performance of the child at school over the course of 6 months.
| Discussion|| |
TCS is an anomaly of craniofacial development as a result of mutations in the TCOF1 gene, which encodes for a nucleolar phosphoprotein known as Treacle, which is a spatiotemporal regulator of ribosome biogenesis. Deficient ribosome biogenesis, in turn, leads to nucleolar stress activation and stabilization of p53, which leads to apoptosis of neuroepithelial cells and consequent loss of neural crest cells. Greater than 60% of the cases arise due to de novo mutation, whereas among 40%, the mutation may be inherited from the parents as in the present case.. Identical mutations which run in the same family are found to be associated with individualized combination of symptoms and variable severity. The severity of the clinical features is found to increase over generations as was found evidently in the presented case with increased number and severity of findings both general and oral in the daughter while compared to the mother.
Dixon et al. also attributed the variation in severity to environmental factors and stochastic events. The patient's mother was working in the “bindi” industry for the last 33 years and exposed daily to polyvinyl acetate (PVA)-based adhesive. The International Agency for Research on Cancer (IARC) has determined that vinyl acetate is possibly carcinogenic to humans (Group 2B). Reproductive/developmental defects have been reported in the form of minor skeletal fetal defects/variants associated with high levels of exposure to PVA, but more commonly secondarily linked to maternal toxicity. The PVA-based adhesive may be a possible occupational factor which modified the disease presentation in the child.
Clinical features manifest as hypoplasia of facial bones, mainly the mandible (78% of cases) and zygomatic complex (81%), considered as an extremely common feature of TCS. In severe cases, the zygomatic arches may be completely absent (Poswillo, 1975). Due to the hypoplasia of the facial bones, a typical bird-like or fish-like face may be seen on presentation. The common manifestations including the presentations of the case are summarized in [Table 1]. An atypical feature, i.e., the ganglion bone cyst was present over the flexor aspect of the right wrist region. Differential diagnosis includes Miller syndrome and Nager syndrome which have additional features such as presence of accessory nipple in the former and thumb/finger anomalies in both syndromes or Goldenhar syndrome which commonly has additional dermoid cysts and vertebral anomalies.
There is no cure for TCS. Treatment is directed at the specific needs for each patient. Many children require a multidisciplinary approach involving a craniofacial team comprising an audiologist, pediatric otolaryngologist, plastic surgeon, psychologist, geneticist, and dental surgeons. Genetic counseling is highly recommended for the affected individuals and their families for awareness and critical support and decision-guiding.
| Conclusion|| |
The diagnosis of Treacher–Collins is based on clinical findings; however, due to its strong predilection for familial incidence, the role of genetic counseling should not be undermined. Once diagnosed, the role of any plausible occupational agents should be assessed for awareness and prevention. The potential association of occupational agents in congenital defects is an area, which requires further investigation. A multidisciplinary approach combined with regular follow-ups and behavioral psychological counseling would be beneficial to the child.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient's parents have given their consent for images and other clinical information to be reported in the journal. The patient's parents understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]