Pathology

The Rieger syndrome: Orofacial manifestations.Case report of a rare conditionJagjit Singh, MDSVKarneev Pannu, MDS^/Gurvanit Lehl,

Rieger syndrome is a rare, autosomal dominant disorder due to developmental arrest of tissues derivedfrom neural crest ectoderm in the third trimester. It is characterized hy abnormalities ot the anterior cham-ber of the eye coincident with dental and craniotaciai anomalies. Early recognition of dentai anomalies aidsin detection of the syndrome and prevents progressive loss of vision. This case report discusses the ocu-lar, dental, and craniofaciai findings and the overall management of the patient. (Quintessence Int2003:34:689-692)

Key words: autosomal dominant disorder, craniofaciai anomaly, genetic disorder, oiigodontia, Riegeranomaiy

CLINICAL RELEVANCE: This paper describes orofacialmanifestations of a rare condition. It is important for den-tal surgeons to be able to defect this inheritable disorderto prevent resultant progressive visual impairment.

Tbe Rieger syndrome is a rare, autosoniai dominantdisorder,' characterized by malformations oí the

eye coincident with dental abnormalities. It was recog-nized as a genetic syndrome hy Rieger̂ who associatedhypodontia with goniodysgenesis (ie, anterior segmentdysgenesis). The frequency of occurrence in the generalpopulation has been estimated to he 1 per 200,000.'No racial or sexual predilection is reported. When onlythe eyes are affected, the condition is termed Riegeranomaly.*

'Senior Resident. Department of Dentistry, Government Medical andCollege Hospital, Chandigarh, India.

^Senior Lecturer. Department of Dentistry. Government Medical andCollege Hospital, Chandigarh, India,

^Reader and Head, Department ot Dentistry, Government Medical ardCollege Hospital, Chandigarh, India.

Reprint requests: Dr Gurvarit Lehl, Department of Dentistry, GovernmentMedical and College Hospital, Sector-32, Chandigarh t60 047, India.E-mail; gvlehlQyahoo.co.uk

The ocular component is usually bilateral andmanifests as a triad of features: hypoplasia of the ¡ris;anterior synechiae (iridocorneal adhesions); and aprominent anteriorly displaced Schwalhe's line. Othersignificant findings may be corneal defects, pupillaryanomalies, cataracts, marked ametropia, and the onsetof juvenile glaucoma.^''

The prominent dental feature is oiigodontia (partialanodontia) in both the primary and permanent denti-tion. Maxillary incisors and canines are the teeth mostoften absent, with premolars occasionally missing.''Other associated tooth abnormalities are microdontia,enamel hypoplasia, cone-shaped teeth, delayed erup-tion, taurodontia, mis-shapen teeth, and shortenedroots.'^-^ A hyperplastic maxillary frenum also hasbeen noted.^^

Characteristic facial features give these patients anaged appearance. Hypopiastic growth of the maxilla iscommonly seen and leads to a mild prognathic profile,a shortened philtrum, pronounced lower lip, and re-ceding upper lip.'** Telecanthus, hypertelorlsm, and awide nasal bridge are occasionally seen.''-̂ Some casesof Rieger syndrome are associated with various othersystemic anomalies, most frequently being failure ofperiumbilical skin to involute.'

The following case report discusses a patient withRieger syndrome, emphasizing the orofacial findings.

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Fig 1 intraoai photograph stiowing peg-siiaped tooth in crossbite, suppiementajytooth, congenitaily missing incisors, andover-retained primary latetai incisors.

Fig 2 (right) Orthopantograin stiowingamount of Done around over-retained teethand congenitaily missing teeth.

Fig 3a Oeit) Fuii (aciai view of the patientshowing ptosis.

Fig 3b (righf) Protile demonstrating re-ceding upper lip and prognathic mandibu-iar profiie

CASE REPORT

A 35-year-old maie patient of average build reportedto the Ophthalmology Outpatient Department of theGovernment Medical College Hospital, Chandigarh,India, with the chief complaint of diminished vision inboth the eyes. Upon examination, the patient wasfound to have very high intraocular pressure in botheyes. To ascertain the cause of glaucoma, gonioscopywas performed, which revealed multiple congenitalanomalies in the angle. These were suggestive ofRieger syndrome. Subsequently, the patient was re-ferred to the dental outpatient department to confirmthe diagnosis of Rieger syndrome.

Orofacial examination

An oral examination including panoramic andcephalometric radiographs was completed. The patienthad three retained primary teeth (right and left maxil-lary lateral incisors and left maxillary second molar).Thirteen permanent teeth were congenitaily missing.The maxillary left lateral incisor was peg-shaped andin crossbite. The mandihular incisors and premolars

were microdontic. A supplementary tooth was presentin the mandibular incisor region (Figs 1 and 2). Mostof the teeth exhibited chalky white hypoplastic areas.A hyperplastic maxillary labial frenum (papilla pene-trating type) was present. Chronic generahzed mar-inai gingivitis was present. The midface was flattenedsince permanent maxillary incisors were missing, lead-ing to relative mandihular protrusion (Figs 3a and 3b).Tbe cephalometric analysis showed a Class III ten-dency with an ANB of 0°. There was maxillary defi-ciency with an SNA of 71° (Table 1, Fig 4). The ab-solute maxillary length was also deficient (42 mm).There was an increase in the length of the anterior cra-nial base. There was loss of curvature of the pinna bi-laterally.

DENTAL TREATMENT PLAN

Retained primary root stumps were extracted. Oralprophylaxis was done for treatment of gingivitis, andplaque-control instructions were given. Restoration ofcarious teeth and an interim removable partial denturewas given to belp in chewing. Correction of tbe incisor

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TABLE 1 Cephalometric analysis of the case

Measurement

Linear (mm)A-PNSSelia-Nasion(anterior crania i base)Nasion-ANSMenton-ANSSella-Basion

Angular (degrees)SNASNBANBFacial angieAngle ot convexity

Normai values

457t.48

52.765.846.2

81,678.53.12

86.51,5

Patient values

4280

617052

71710

842

Fig 4 Cephalogram tracing showing itie reievant anguiar and iin-ear measurements.

in crossbite and extraction of retained primary lateralincisors were planned to fabricate a fixed partial den-ture for the maxillary anterior region.

Ophthalmic examination

Ocular examination of the patient revealed bilateralcongenital mild ptosis witb best corrected visual acuityof 20/80 in tbe right eye and 20/30 in the left eye. Slitlamp biomicroscopic and fundus examination by-H90D lens revealed stromal atropby of tbe iris, ectro-pion uvea, and advanced glaucomatous cupping witba cup-disc ratio of 0.8:0.9 in both eyes. Intraocularpressure by applanation tonometry was 48 mm Hg inthe right eye and 40 mm Hg in the left eye.Gonioscopy revealed prominent Schwalbe's line withhigh insertion of the iris on trabecular meshwork andiridocorneal adhesions in the angles of both eyes.Humphrey visual field testing showed tubular field ofvision in both eyes. Control of intraocular pressure inboth eyes was achieved by antiglaucoma drugs, fol-lowed by trabeculectomy with intraoperative mito-mycin-c application in botb eyes with good control ofintraocular pressure postoperatively (8 and 10 mm Hg,respectively, in right and left eyes).

DISCUSSION

Very few cases of Rieger syndrome are documented inthe dental literature,^'' This patient had findings com-patible with Rieger syndrome. The criteria necessaryfor the diagnosis of Rieger syndrome are characteristicchanges in the anterior chamber of the eye associatedwitb various dental anomalies. Hypodontia is the most

common dental anomaly associated with this syn-drome. Failure of periumbilical skin to involute is alsoan important element in tbe diagnosis. An array of nu-merous congenital dental, craniofacial, and somaticanomalies have been reported in the dental literature."Microdontia is also a frequent finding in primary, aswell as permanent dentition, and varies in number ofteeth involved and severity of size reduction.' Themost commonly affected teeth are incisors, which mayhe peg-shaped.^ Delayed eruption of teeth also hasheen descrihed,* A mild form of enamel hypoplasiaalso has been noted. Lingual or maxillary labial frenfialso have been found to be byperplastic' This patientbad all tbe above mentioned findings, wbicb coincidewitb reports of otber authors.•'•̂ •̂ In addition, a super-numerary (supplementary) tooth was observed in themandibular incisor area. This patient had 13 perma-nent teeth congenitally missing. Maxillary hypoplasiais a common skeletal characteristic in patients withRieger syndrome. In this case, cephaiometric analysisshowed a Class III tendency with an ANB of 0°. Theabsolute maxillary length was also deficient. Althoughmaxillary hypoplasia is commonly found, some pa-tients have been reported to have mandibular hy-poplasia as well,* Usuaily there is hypoplasia of thepremaxilla because of missing anterior teeth,'

One craniofacial anomaly in this patient was loss ofcurvature of the pinna of the ear. Ophthalmologic ex-amination revealed increased ocular pressure, promi-nent Schwalbe's line, and iridocorneal adhesions in theangles of both eyes. Increased ocular pressure occursbecause of adhesions from the iris to the trabecularmeshwork that obstruct the outflow of aqueoushumor,'" The diagnosis of Rieger syndrome can be dif-ferentiated from other anterior chamber malformation

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syndromes (Axenfeld's syndrome, Peter's anomaly, orgoniodysgenesis associated with juvenile glaucoma) bypresetice of characteristic dental abnormalities.

A vast number of developmental defects have beenlinked with the Rieger anomaly. Eadier theories on itsetiology postulated that the anomalies were a result ofmesodermal maldevelopment,' but recent histopatho-logic reports support a theory of developmental arrestof tissues derived from neural crest ectoderm in thethird trimester.•'^ Differentiation and migration ofneural crest cells are responsible for the formation ofnormal ocular and eraniofacial structures, includingbones and cartilage of the face, dental papillae, pitu-itary gland, ocular structures, and the umbilical ring.Developmental disturbance of these may explain themorphologic abnormalities, the maxillary andmandihuiar hypoplasia, hypertelorism, teeth, and fail-ure of involution of periumbilical skin.'^ At the geneticlevel, the Rieger syndrome is an autosomal dominantcondition associated with mutations in the PITX2 geneat chromosome 4q25. a PAX6 gene abnormality atchromosome 13ql4," while gene FKHL7 at chromo-some 6p25 is associated with the Axenfeld-Riegeranomaly.'- None of the available immediate familymembers of the patient had this anomaly.

CONCLUSION

The present case report describes a rare combinationcase of ocular and dental abnormalities. It occurs dueto developmental arrest of tissues derived from neuralcrest ectoderm in the third trimester. This case hadclassic findings resembling Rieger syndrome. Hypo-dontia is a relatively common finding in the generalpopulafion. It is important for the dentist to identifythis condition, obtain an ophthalmologic examinationof these patients to rule out this syndrome, and pre-vent loss of vision.

ACKNOWLEDGMENTS

The aurhori w.iuld like lo thank Dr Sunandan Sood, Professor andHead, Department of Ophthalmology. Government Medical andCullcgc Ho.spital, Sector 32. Chandigarh, India, for the ophthalmo-logic management of the case, and Dr Arti Dafiiya, Senior Resident,Deparlment oT Orthodontics, Oral Health Sciences Centre,Poslgraduale Institute of Medical Education and Research, Chan-digarh, for her help in preparation of this manuscript.

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