39European Archives of Paediatric Dentistry // 8 (Suppl. 1) 2007

Case Reports: Rieger Syndrome

Skogedal N, Nordgarden H.TAKO-centre, Lovisenberg Diakonale Hospital, Oslo, Norway.

Key words: Rieger syndrome, hypodontia, frenulum, treatment

Postal address: Dr Skogedal. TAKO-centre, Lovisenberg Diakonale Hospital, 0440 Oslo, Norway.

Email: nina.skogedal@tako.no

Abstract:

Background: Rieger syndrome is a rare autosomal domi-

nant condition with at least three genetic forms. The main

symptoms are umbilical cord anomalies, malformations of

the anterior chamber of the eye, agenesis of certain teeth,

and a hypoplastic mid-face. Case reports: In this paper

three cases of Rieger syndrome are presented, focusing in

particular on dental and craniofacial findings. Treatment:Treatments have been individualized and include temporary

dentures and restoration of primary teeth to preserve them

until their successors erupt. Follow-up: Patients with Rieger

syndrome should be followed according to an individualized

plan, depending on the severity of dental symptoms and

general caries risk. Conclusion: It is important that the den-

tal team have knowledge about this syndrome, as ocular

complications can be prevented if the diagnosis is made

early.

Introduction Rieger syndrome (RS) is a rare, autosomal dominant condi-

tion with almost complete penetrance and variable expres-

sivity. The syndrome is characterized by periumbilical, ocu-

lar, craniofacial, and dental abnormalities [Winter and

Baraitser, 1996]. Failure of involution of periumbical skin has

been reported to be a cardinal symptom [Jorgensen et al.,

1978]. Ocular features comprise iris stromal hypoplasia

causing the eyes to appear dark, and strands of iris tissue

crossing the anterior chamber angle. Schwalbes line may be

anteriorly displaced. Craniofacial features are dominated by

an underdeveloped premaxilla and a relative mandibular

prognathism. Oral anomalies comprise hypodontia, espe-

cially of maxillary front teeth both in the primary and the per-

manent dentitions, small teeth, peg-shaped front teeth, and

hyperplastic upper labial frenulum. Other teeth may also be

missing.

To date, RS has been associated with the genes PITX2 on

chromosome 4q25 [Semina et al., 1996] and FOX-C1 on

chromosome 13q14 (Phillips et al, 1996). Also one case

report describing an association between the syndrome and

PAX6 on chromosome 11p13 has been published [Riise et

al., 2001]. This case is identical to one of the cases (Case 1)

described in this report. Three cases seen at the TAKO-cen-

tre, Lovisenberg Diakonale Hospital, Oslo, Norway are pre-

sented. The TAKO-centre is a national resource centre aim-

ing to provide multidiciplinary expertise in diagnostics and

oral treatment planning in persons with rare medical condi-

tions. Written consents to publish all photographs have been

obtained.

Case reports Case 1. A 14-year-old girl with healthy, unrelated parents

had been diagnosed and treated for characteristic ocular

features since she was 6 weeks old. There was also failure

of involution of the periumbilical skin. As she grew older, the

ophthalmologist recognized her flat mid-face and missing

maxillary central incisors. She was referred to the TAKO-

centre when she was seven years of age for an examination

with regard to a possible syndrome diagnosis. At that time

she had the diagnosis partial aniridia. She had a retrognath-

ic premaxilla and a mixed dentition with peg-shaped 52 and

62 as the only maxillary incisors present (Fig. 1a). A detailed

medical and dental history revealed that teeth 51 and 61

had always been missing. Erupted permanent teeth were:

16, 26, 36, 32, 31, 41, 42 and 46. The lower incisors were

peg-shaped and slender, and all teeth were small.

The patient had an open bite with unilateral cross-bite.

The palate was shallow and the maxillary labial frenulum

was hyperplastic. Orthopantomogram and periapical

radiographs revealed agenesis of 7 permanent maxillary

teeth: 15, 13, 12, 11, 21, 23, and 25 (Fig. 1b).

Figure 1a. Case 1.

Anterior view of at 7 years

of age showing congenitally

missing central incisors.

Figure 1b. Case 1.

B. Radiograph

taken at 7 years

of age showing

congenital absence

of 15, 13, 12, 11,

21, 23, and 25.

40European Archives of Paediatric Dentistry // 8 (Suppl. 1) 2007

Skogedal and Nordgarden

Treatment. Frenectomy was performed when she was 8

years old. After eruption of 22, composite restorations of 52

and 22 were made. Composite resin was also used on the

buccal surfaces of 53 and 63 for retention of a partial den-

ture, which replaced the central incisors. The patient was

satisfied with the aesthetic result (Fig. 2a).

Follow-up. After completed treatment she has been seen

annually in our clinic. A new partial denture was made after

one and a half years due to loss of the first one. All perma-

nent teeth are now erupted, but maxillary growth has been

slow (Fig 2b), and the denture is still in use. Future planned

treatment includes orthodontic therapy starting when 52 is

lost, and 22 will be moved distally to give more room for

replacement of 12, 11 and 21. Remaining primary teeth will

be kept as long as possible. Dental implants are the most

likely treatment for the patient at the age of 18-20 years of

age and it may be necessary to perform orthognatic surgery

because of the relative mandibular prognathism.

Based on information revealed in taking the medical history

and clinical findings, he was further referred to an ophthal-

mologist who reported hypoplasia of the iris stroma and an

asymmetric pupil, thereby confirming the tentative diagnosis

of Rieger syndrome. His intraocular pressure is now being

measured annually, as glaucoma is a common complication

in this condition.

The patient was also referred to a geneticist for consultation

and genetic analysis. Results have still not been received.

Treatment. The patient has only been seen once at our clin-

ic, at age 13 years, after the diagnosis had originally been

made. At this time teeth 13 and 23 were erupting, 23 was

erupting mesially for 63 and 53 had exfoliated. He had tried

to use a partial denture, but it did not fit well. The maxillary

labial frenulum was hyperplastic (Fig 3c). All teeth were

small. He had a bilateral cross-bite and mesial occlusion

with negative overbite of 4mm. OPG revealed taurodontia of

all permanent molars. The roots on 75 and 85 were short.

Follow-up. The following recommendations were given

based on the clinical findings. At this stage of tooth devel-

opment it is challenging to make a successful denture.

However, this was recommended after a frenectomy. which

was necessary as he could not pout his lips, and the frenu-

Figure 2a. Case 1.

Anterior view at 9 years of age

with a partial denture in place.

Figure 3c. Case 2.

Anterior view at 13 years of age

showing congenital absence of

four maxillary incisors.

Figure 3a. Case 2.

Profile at the age of 13,

note the relative mandibular

prognathism.

Figure 2b.Case 1.

Radiograph at 13

years of age, note

that 55, 52 and 65

are still present.

Figure 3b. Case 2.

Radiograph taken

at 13 years of age

showing congenital

absence of 17, 12,

11, 21, 22, 25, 35,

and 45, also note

the short roots on

75 and 85.

Case 2. A local dental hygienist participating in a post-grad-

uate program first suspected a syndrome diagnosis in a 12-

year-old boy and consulted staff at the TAKO-centre. He had

previously been diagnosed with oligodontia (8 teeth miss-

ing), malocclusion, hypoplastic premaxilla (Fig. 3a), and

hyperplastic upper labial frenulum by the local dentist.

Earlier records from dental visits were obtained and sent to

us. These included clinical photographs and an orthopanto-

mogram. The radiographs revealed agenesis of 17, 12, 11,

21, 22, 25, 35, and 45 (Fig. 3b). His facial appearance and

his dark coloured eyes suggested Rieger syndrome. He was

also using glasses. Further information was obtained by the

local dental hygienist and included reports of a rapid decline

in sight. Despite this he had not been seen by an ophthal-

mologist for several years. He had been operated on for her-

nia umbilicalis when he was 3 months old.

41European Archives of Paediatric Dentistry // 8 (Suppl. 1) 2007

Rieger syndrome

lum was an obstacle for a pre-temporary denture. Later it

may be necessary to perform orthognatic surgery. Two or

four dental implants will be placed in the maxilla, depending

on the position of the canines; 65 should be preserved as

long as possible; 75 and 85 may be extracted or replaced by

implants depending on the future orthodontic treatment.

Case 3. An 8-year-old boy was referred to the TAKO-centre

six years ago from a clinical geneticist. His mother suspect-

ed a diagnosis of Rieger syndrome in both herself and her

son. The mother had all her life had problems due to multi-

ple dental agenesis, mainly in the maxilla. In addition she

had had hernia umbilicalis and eye-problems, with dark-

coloured eyes that were different from other family-mem-

bers. Her son had been operated for hernia umbilicalis. He

demonstrated frontal bossing, retrognathic premaxilla with

relative mandibular prognathism, thin upper lip and a pro-

truding lower lip. His eyes were dark-coloured. He had 16

primary teeth; the teeth missing were 53, 52, 62 and 63. 51

and 61 had normal size, but all other teeth were small. The

maxillary labial frenulum was hyperplastic and the median

diastema was large (Fig 4a). Radiological examination

revealed that 53 and 63 were present, but their development

was delayed. Agenesis of 52 and 62 was confirmed. Only

one permanent incisor could bee identified.

Clinical findings were consistent with the orofacial and den-

tal symptoms of Rieger syndrome and the boy was referred

to an ophthalmologist. The first examination did not reveal

any pathological eye findings, possibly because there were

cooperation problems. However, at a follow up 2 years later

atrophy of the iris stroma and anteriorly displaced

Schwalbes line were diagnosed, and he was finally diag-

nosed with Rieger syndrome. Since then he has been seen

regularly in our clinic.

Treatment. At present 51 and 61 are still not exfoliated, but

they are slightly mobile. Tooth development proceeds very

slowly. No treatment has been performed so far. An

orthopantomogram revealed agenesis of teeth: 17, 16, 12,

21, 22, 26, 27, 47 (Fig. 4b). He has a mandibular prog-

nathism with no transverse deviation (Fig. 4c).

Follow-up. Unless the patient wants a semi-permanent den-

ture, no treatment will be initiated until exfoliation of 51 and

eruption of 11, later shedding of 61 and eruption of 22.

Frenectomy will be done and a semi-permanent prosthetic

treatment in the maxillary anterior teeth, eventually com-

bined with orthodontic therapy. Later, orthognathic surgery

will probably be performed. The parents were informed that

for the moment we can not ascertain that all tooth germs will

develop to a normal size.

Discussion:Dento-facial features may be the first recognizable symp-

toms of Rieger syndrome. As ocular complications can be

prevented with early interventions, it is important that den-

tists have knowledge about this condition. Furthermore,

early diagnosis and an interdisciplinary approach is neces-

sary in order to provide the best short and long-term treat-

ment plans as well as treatment and follow-up for individu-

als with the syndrome.

Acknowledgements.Consent to report these cases and to use facial photographs was obtained

from the parents of the three children involved.

References:Jorgenson RJ, Levin LS, Cross HE, Yoder F, Kelly TE. The Rieger syndrome.

Am J Med Genet 1978;2:307-318.

Phillips JC, del Bono EA, Haines JL,et al. A second locus for Rieger syndrome

maps to chromosome 13q14. Am J Hum Genet 1996;59:613-619.

Riise R, Storhaug K, Brøndum-Nielsen K. Rieger syndrome is associated with

PAX6 deletion. Acta Ophthalmol Scand 2001;79:201-203.

Semina EV, Reiter R, Leysens NJ, et al. Cloning and characterization of a

novel bicoid-related homeobox transcription factor gene, Rieg, involved

in Rieger syndrome. Nat Genet 1996;14:392-399.

Winter R, Baraitser M. London Dysmorphology Database. Oxford Uk. Oxford

Medical Press, 1996.

Figure 4a. Case 3.

Profile view at 8 years of age,

note the negative overjet.

Figure 4a. Case 3.

Anterior view at 2 years of

age showing a hyperplastic

labial frenulum and broad

diastema mediale.

Figure 4b. Case 3.

Radiograph taken

at 8 years of age

showing agenesis

of 17, 16, 12, 21,

22, 26, 27, and 47.