Journal of Indian Society of Pedodontics and Preventive Dentistry
Journal of Indian Society of Pedodontics and Preventive Dentistry
                                                   Official journal of the Indian Society of Pedodontics and Preventive Dentistry                           
Year : 2006  |  Volume : 24  |  Issue : 5  |  Page : 27--30

Rubinstein Taybi syndrome

A Stalin, Balagopal R Varma, Jayanthi 
 Department of Pedodontics and Preventive Dentistry, Ragas Dental College and Hospital, Chennai, India

Correspondence Address:
Balagopal R Varma
Prof. and Head of Dept., Mam Amritamai Dental College, Cochin, Kerala


Rubinstein Taybi syndrome or Broad Thumb and Hallux syndrome is a genetic multisystem disorder characterized by facial dysmorphism, growth retardation and mental deficiency. A ten-year-old boy who had come to the Department of Pedodontics, Ragas Dental College, Chennai, with the chief complaint of unaesthetic appearance with extra teeth revealed delay in the developmental milestones. The patient appeared to be hyperactive and mentally retarded. Extra oral features revealed distinctive facial appearance with a broad fore head, hypertelorism, broad nasal bridge and beaked nose. Intra oral features observed were talons cusps in the upper central and lateral incisors, mesiodens, carious teeth and plaque accumulation. Since the patient was hyper active and mentally retarded, the dental treatment was done under GA. The treatment plan and dental management of this patient are discussed in this case report.

How to cite this article:
Stalin A, Varma BR, Jayanthi. Rubinstein Taybi syndrome.J Indian Soc Pedod Prev Dent 2006;24:27-30

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Stalin A, Varma BR, Jayanthi. Rubinstein Taybi syndrome. J Indian Soc Pedod Prev Dent [serial online] 2006 [cited 2020 Apr 9 ];24:27-30
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Rubinstein Taybi syndrome or (RSTS) or Broad Thumb and Hallux Syndrome is a genetic multisystem disorder characterized by facial dysmorphism, broad thumbs and halluces, growth retardation and mental deficiency.[1],[2] Though first described by Michael in 1957 in the French literature, it was named after Jack Herbert Rubinstein and Hooshang Taybi who identified the constellations of a recognizable syndrome in 1963.

Prevalence in general population ranges from 1/3,00,000 to 1/720,000 persons. Hennekam and others found it to be 1/1,25,000 among the people of Netherlands.

Although the history of consanguinous marriage, familial recurrence and apparent dominant transmission were described in the pathophysiology of this syndrome, the overwhelming majority of the reported cases are sporadic.

Regarding the genetic background of Rubinstein Taybi syndrome, the locus of Rubinstein Taybi syndrome is located on band 16 p13.3 restricted to a region containing the gene for transcription cofactor CRE binding protein (CBP-cyclic adenosine monophosphate response element binding protein). Microdeletions at 16p 13.3, point mutations in the CREB and reciprocal translocation between chromosomes 7 & 16 and chromosomes 2 & 16 were also found in RSTS patients (Petrij et al 2000).[3]

Systemic problems involving respiratory systems, feeding and weight gaining are noted during infancy. Polyhydromnios has been reported in 30% of pregnancy in mothers of RSTS cases. Systemic manifestations involving the skin, eye, ear, CVS, CNS, RS, Urinary tract sysyem, Skeletomuscular system are also common among the RSTS cases.

Length, weight and head circumference at birth is between 25th-50th percentiles. Mental deficiency is characteristic and there is severe delay in expressive speech. Average IQ reported in these cases is 51. Electroencephalographic abnormalities, seizures, absence of corpus collosum and hyperactive deep tendon reflexes have been reported. Incomplete or delayed descent of the testes has been seen in males.[1]

Broad thumbs and great toes have been reported in most of the cases. Broad terminal phalanges, persistent fetal pads, clinodactyly of the 5th finger and overlapping of toes are common.

Craniofacial features include microcephaly, prominent forehead, down slanting palpebral fissures, epicanthal fold, strabismus, broad nasal bridge, beaked nose with the nasal septum extending below alae, high arched palate and mild micrognathia. Grimacing or unusual smile, long eye lashes, nasal lacrimal duct obstruction, ptosis of eyelids, congenital or juvenile glaucoma, refractive error and rotation of ears are also common. Low frequency abnormalities included bifid uvula, submucous patal cleft, bifid tongue, macroglossia, short lingual frenum, neonatal teeth and thin upper lip. Talons cusp have been observed in over 90% of cases with RSTS.[3],[4]

Differential diagnosis can be a problem in the newborn. Occasionally some cases have been confused with de Lange syndrome, Saethre Chotzen syndrome or with Trisomy 13. Broad thumbs may be observed in Apert syndrome and Pfeiffer syndrome and short thumbs and fingers are seen in type D brachydactyly.

 Case Report

A 10-year-old boy accompanied by parents reported to the outpatient center of Ragas Dental College, Chennai, with a complaint of unaesthetic appearance with extra tooth in the upper anterior region. The prenatal and natal history of the child was uneventful. The clinical history of the patient revealed that the developmental milestones were delayed and the child is aphasic since childhood. The patient was the first, of 2 children of parent with no history of consanguinity. The patient appeared mentally challenged and hyperactive [Figure 1]. He appeared to be of short stature for his age. He does not go to school / but has no problem in socializing with others.

The patient had a distinctive facial appearance with a broad forehead, hypertelorism, broad nasal bridge, beaked nose, thin upper lip and unusual grimace [Figure 2]. Preliminary investigations ruled out any CNS or CVS involvement.

On examining hands, short fingers, broad thumbs and broad terminal phalanges and clinodactyly of the 5th finger were noted [Figure 3]. The toes of the feet were short with broad great toes and clinodactyly of 3rd toe [Figure 4]. Radiographs of hands revealed broad terminal phalanges and clinodactyly of 5th finger [Figure 5]. Radiographs of feet showed broad great toes and clinodactyly of 3rd toe [Figure 6]. Radiographs of chest and pelvis did not show any abnormal findings.

Intraoral examination showed poor oral hygiene with plaque and calculus deposits on facial surface of lower anterior teeth and gingival inflammation in upper and lower anterior region. A high arch palate with marked anterior open bite and bilateral posterior cross bite were noted [Figure 7]. In this mixed dentition stage, the following permanent teeth have erupted - the first molars, central and lateral incisor. The lower 1st premolar was seen erupting in both sides [Figure 9]. The teeth present were: 16, 55, 54, 53, 12, 11, 21, 22, 63, 64, 65, 26, 36, 75, 34, 32, 31, 41, 42, 83, 44, 85 & 46.

A supernumerary tooth was seen adjacent to incisive papilla in relation to 21. Talon cusps were present on maxillary central and lateral incisors [Figure 8]. The talon cusp on the right maxillary central incisor was bifid with a bigger left lobule and smaller right lobule and extended from CEJ halfway to the incisal edge. The talon cusp on left maxillary central incisor is attached to the palatal surface 0.5 mm distal to the midline of the tooth. The talon cusps on maxillary lateral incisors were prominent cusp like structures attached to palatal surface in the midline of the tooth extending from CE junction halfway to the incisal edge. In all the incisors with talon cusps, there were a deep developmental groove where the cusp blends with the sloping lingual tooth surface.

The lower right deciduous canine tooth (83) showed pre-shedding mobility. Dental caries was observed in the occlusal surface of mandibular right first permanent molar (36). It was symptomless.

An intraoral radiograph showed a 'W' shaped radiopaque structure superimposed on the right maxillary central incisor [Figure 10]. It also showed a 'V' shaped radiopaque structure superimposed on the image of the maxillary left central incisor with the point of 'V' toward the incisal edge. Both the talon cusps were outlined by two distinct white lines converging from the cervical area of the tooth towards the incisal edge. None of the teeth with talon cusps showed pulpal involvement of carious process / extension of pulp chamber into the talon cusp region. OPG or any other extraoral radiographs could not be taken, as the patient was hyperactive.

After the complete clinical examination and investigation, the following dental treatment plan was derived.

1. Oral prophylaxis and topical fluoride application.

2. Class-I cavity preparation and Composite resin restoration on tooth-36.

3. Reduction of talon cusps followed by preventive resin restorations on the grooves of teeth -11,12,21,22.

4. Extraction of mesiodens and 83.

5. Review and recall

Considering the mental retardation and hyperactive deficit in this case, all the treatment was done under general anesthesia.

The patient recalled on the second day [Figure 11][Figure 12] of the treatment procedure and oral hygiene instructions were given to the patient as well as his parents. Parents were told about the importance of dental health and review visits in the future.

Patient reported again after the period of 11 months. Intra oral examination revealed intact restorations, no new carious lesions and better gingival health and oral hygiene. The teeth - 17, and 24, 27, 33, 43 were seen to be erupting [Figure 13][Figure 14]. In this visit, a general physician observed no other medical problems.


Rubinstein Taybi syndrome is a rare multiple congenital anomaly syndrome with only 600 cases reported worldwide. DG Fardner and SS Girgis (1986) have observed talon cusps in over 90% cases whereas Hennekam RCM and Van Dorne JM after studying 45 cases of RSTS in Netherlands reported that 92% of them had talon cusps. Talon cusps are also present in 1% of normal population. Talon cusp is an unusual and rare morphologic anomaly.[1] Thoma reported the first case in 1892 and later by Mitchell in 1952. It is called so because it resembles an eagle's talon.

Early diagnosis and management of talon cusp is important for the sake of preventing occlusal interference, compromised esthetics, carious developmental grooves, periodontal problems due to excessive occlusal forces and irritation of the tongue during speech and mastication.[5]

Treatment modalities for talon cusp include prophylactic placement of sealants in the developmental groove, recontouring, periodic reduction of the talon cusp followed by topical fluoride application and endodontic treatment in cases which result in pulp exposure. In this case, neither caries involvement in pit and fissure areas nor occlusal interference was noted. But the presence of talon cusps in all the incisors in the upper jaw seems to be unaesthetic and prone to plaque accumulation and caries development. So, the treatment carried out was reduction of extra cusps, recontouring the lingual surface of the incisors and preventive resin restorations.

Most authors reported talon cusp to be composed of normal enamel, dentin and pulp. Others have dismissed the presence of the pulpal extension on the basis of histological and microscopic examinations. The radiographs in this report indicated the absence of pulp tissues in the talon cusps.[6]

Hennekam RCM and Van Dorne JM also suggested that hypodontia, malformed teeth, natal teeth and hyperdontia can be manifested in this syndrome. This patient had a supernumerary tooth adjacent to incisive papilla in relation to 21. The rarity of the RSTS coupled with the fact that this case presents with prominent talon cusp on all four incisors, bifid talon cusp in upper right central incisor and presence of a supernumerary tooth palatal to 21 makes this case an interesting and unique one.

In most patients with such syndromes, the emphasis on care required is on the primary disabling condition and so they often receive inadequate dental care. This is particularly unfortunate, since oral health and function are essential to the overall health and well being of growing children, including those with disabilities. The comprehensive care required by these patients is time consuming and many patients as well as their families are unco-operative.

The dentist who extends his responsibility beyond the treatment of the "Chief Complaint", however, will find great rewards in helping the disabled patients and his family.


1Gorlin RJ, Cohen MM, Hennekam RC. Proportionate short stature syndrome: Syndromes of the head and neck. 4th ed. Oxford University Press: USA; 2001. p. 382-7.
2Shafer WG, Hine MK, Levy BM, Tomrich CE. Disturbances of development and growth; Developmental disturbances of oral and Para oral structures. 4th ed. W B Saunders: India; 1993. p. 41.
3http// egi? index-565.
4Rubinnstein Taybi Syndrome: RSTS-Pubmed ID-180849.
5Segura JJ, Jimenez-Rubio A. Talon cusp affecting permanent maxillary lateral incisors in 2 family members. Oral Surg Oral Pathol Oral Radiol Endod 1999;88:90-2.
6Nadkurni UM, Munshi A, Damle SG. Unusual presentation of talon cusp: two case reports. Int J Pediatr Dentist 2002;12:342-5.