Afnan Al-Saleem, Asma Al-Jobair**
How to CITE:
J Pak Dent Assoc 2010;19(1): 49 - 53
Williams syndrome is a rare genetic syndrome with distinctive craniofacial features, cardiovascular abnormalities, and behavior characteristics including mental retardation. This case report describes the facio-dental characteristics in a case of Williams syndrome and discusses the problems that may confront the dentists while treating children with Williams syndrome.
Williams syndrome, clinical manifestations, facio-dental characteristics, medical considerations.
Williams Syndrome (WS) also Williams -Beuren Syndrome is a rare, multisystem genetic disorder first identified as a distinct clinical entity by Williams et al in 19611. It is present at birth and affects boys and girls equally2 .Williams syndrome is estimated to effect between 1:7500 and 1:20000 live births2,3 . The syndrome represents a developmental disorder caused by a hemizygous deletion of the elastin gene on chromosome 7q11.234,5. Williams syndrome is characterized by dysmorphic facies, cardiovascular
diseases, mental retardation, and a characteristic cognitive profile 2 , 6 – 8 . In addition, infantile
hypercalcaemia, hoarse voice, hyperacusis (increased sensitivity to sound), endocrine abnormalities, growth retardation, orthopedic problems and renal abnormalities may also be associated 9-12
Due to variability in the clinical findings, diagnosis is usually made during mid-childhood when the characteristic facial features, cognitive profile and cardiac findings become more apparent 13. The diagnosis is usually confirmed by chromosomal fluorescent in-situ hybridization analysis, detecting submicroscopic deletions of 7q11.2313, 14. Early diagnosis of WS is important, as many of its features necessitate treatment and the prognosis can be significantly improved by appropriate time management. Facial appearance is considered to be a diagnostic feature in patients with WS. A dentist can be of help in diagnosing Williams syndrome early. Individuals with WS have distinctive facial appearance including broad brow, periorbital fullness, a stellate/lacy iris pattern, strabismus, short nose, full nasal tip, depressed nasal bridge, long philtrum, full lips, wide mouth, and prominent earlobes 2,15,16. Young children have epicanthal folds and full cheeks, while adults typically have a long face and neck
Beuren in 1964, independently described the syndrome noting also typical dental anomalies17. Several studies have reported increased frequency of dental abnormalities in WS. These anomalies may include microdontia, hypodontia, enamel hypoplasia, excessive interdental spacing, primary tooth resorption anomaly and malocclusion 18-20. The purpose of this paper is to describe the clinical manifestations of a child with Williams syndrome with particular emphasis on facio-dental characteristics and to discuss the medical considerations in dental management of children with Williams syndrome.
An 8-year-old Saudi boy diagnosed with Williams Syndrome presented for dental care at Pediatric Dentistry Clinics at Security Forces Hospital, Riyadh, Saudi Arabia. The boy was born through full term pregnancy and the delivery was uneventful. The family history did not reveal any further occurrence of WS. The child was diagnosed to
have pulmonary artery stenosis at birth which improved by the age of 6 years. The child had mild mental retardation and was hyperactive. The patient was 110 cm tall and weighing 19 kg at initial visit. The patient displayed the characteristic “elfin face” appearance including full prominent cheek, periorbital fullness, mild hyperopia (vertical strabismus), wide mouth with thick lips, long philtrum, small nose and depressed nasal bridge (Fig.1.a & b).
The patient had no previous dental visit. Upon intraoral Examination, folding and thickening of the buccal mucous membrane, severe hypocalcification of the primary teeth with extensive carious lesions and poor oral hygiene were observed (Fig.2.a & b).
All the permanent lower incisors were erupted except for the lower left lateral incisor. Molar relationship was class I with posterior crossbite on the left side, while incisor relationship showed normal overbite and overjet. The panoramic radiograph demonstrated a mixed dentition with multiple carious lesions and congenitally missing lower left lateral incisor and the upper third molars. The stage of eruption between the permanent and the primary teeth was normal according to age. Cephalometric radiograph was also taken. Cephalometric measurements showed an anterior inclination of the maxilla, a high mandibular plane angle, and a deficient bony chin. Due to the total lack of cooperation, and the amount of dental treatment required, it was decided to perform dental treatment under general anesthesia. Clearance from
general anesthesia department was obtained, and the patient was labeled as ASA II patient according to the American Society of Anesthesiology classification. During the treatment, all the primary teeth were extracted with suture placement, while all the first permanent molars were restored with amalgam and composite resin. Scaling was performed and topical fluoride was applied. Dental treatment was done under general anesthesia which underwent without complication, and the patient left the operation room in good condition. At one-week recall, all sutures were removed. After orthodontic consultation, lingual arch space maintainer was cemented in the lower arch, while Nance appliance space maintainer was cemented in the upper arch in the following visits,
Most cases of Williams syndrome result from a spontaneous new deletion, but few cases have arisen through parent-to-child transmission21. Microscopic deletion of elastin (ELN) gene explains some of the characteristics of WS, such as some of the facial features, hoarse voice, soft skin, hernias, cardiovascular stenosis and orthopedic problems such as lax joints22. This patient had mild pulmonary artery stenosis which did not necessitate intervention. About 20% of WS cases have peripheral pulmonary artery stenosis in infancy and usually improves over time22. In addition, the patient has mild mental retardation like most of the cases of WS who have mild to moderate mental retardation. The pathogenesis of mental retardation, and the unique personality traits, remains unexplained in these children22. Furthermore, Williams syndrome children are also characterized by anxiety, insecurity and hyperactive behaviors23. This patient was under weight and height, as most of WS infants who born overdue and with a lower birth weight than other siblings. These children exhibit poor weight gain with many being labeled as “failure to thrive”. The mean adult height has been reported to be in the lower third percentile as these children grow up 24 . The present case manifested the facial characteristics of WS. The facial features do change over time and make the diagnosis more difficult, particularly in older patients. The facial dysmorphology affects skeletal and soft tissue apparatus.Mass and Belostoky25 studied the skeletal components of the craniofacial region in eight WS
children with age ranging from 4 to 12 years; and identified four skeletal features which contributed to the facial appearance in WS; short anterior cranial base length, steep mandibular plane, low posterior facial height, and deficient bony chin. This patient also had hyperopia; hyperopia and esotropia (inward strabismus)26 are found in 30 to 78 % of these cases .
The lower left permanent lateral incisor and upper third molars were congenitally missing in this patient. Axelsson et al 19 , reported that one or more of the permanent teeth were missing in 40% of Williams syndrome children. The primary teeth were extensively carious in the present case
which might be due to enamel hypoplasia, poor oral hygiene and the lack of oral health awareness. High caries prevalence has been reported in primary teeth of WS children as compared to normal population 27. Hypoplastic 2 enamel has been reported in 50% of WS cases . The child also presented with malocclusion that required an orthodontic consultation. The orthodontist advised to maintain the space by using upper and lower space maintainers till more definitive orthodontic plan is formulated.
Cardiovascular diseases and the lack of cooperation are the main problems that confront the dentists with WS children who need dental treatment. About 80% of WS individuals have cardiovascular defects, in which the majority has supravalvular aortic stenosis (48-64%) 2, 28. Furthermore, about 80% of the cases also show generalized anxiety disorders 22. The presence of such condition requires special attention and medical consultation before dental treatment.
Congenital heart defects necessitate the reduction of anxiety (usually evoked by dental treatment) and the administration of prophylactic antibiotics for the prevention of subacute bacterial endocarditis (SBE)29. All the children with Williams syndrome should have a careful cardiac assessment before undergoing general anesthesia for dental procedures and pediatric anesthetist consultation must be performed. Several reports of unexpected deaths in WS patients have been associated with the administration of anesthesia30. The physician in the present case approved the treatment under general anesthesia after complete investigation as the child had only a very mild pulmonary artery stenosis which was functionally not significant and did not require any prophylactic antibiotic for SBE. With special attention to the patient evaluation, the treatment under general anesthesia seems more appropriate for WS children and adolescents, especially in those with high treatment needs and low cooperation29. Hyperacusis has been frequently described in WS patients, which should be recognized as an important characteristic finding. This phenomenon should be evaluated before the dental treatment. Dental equipments such as suction and drill can trigger hyperacusis, which might lead to increase anxiety and decrease cooperation. For patients suffering from hyperacusis, it is recommended to work for 5 seconds of dental drilling then 10 seconds off – 5 seconds on, 10 seconds off – until the job is done 31
Early dental evaluation and parental counseling are important especially in these children. The present case had no previous dental visit which reflects the unawareness of the parents as well as the treating physician. The American Academy of Pediatrics recommends dental refe rral of WS children after the age of 1 year22. Preventive dental regimens , nutritional counseling, and restorative treatments must be individually designed and implemented for maximizing the quality of life in WS patients
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