A possible cranio-oro-facial phenotype in Cockayne syndrome

Abstract

Background: Cockayne Syndrome CS (Type A - CSA; or CS Type I OMIM #216400) (Type B - CSB; or CS Type II OMIM #133540) is a rare autosomal recessive neurological disease caused by defects in DNA repair characterized by progressive cachectic dwarfism, progressive intellectual disability with cerebral leukodystrophy, microcephaly, progressive pigmentary retinopathy, sensorineural deafness photosensitivity and possibly orofacial and dental anomalies.

Methods: We studied the cranio-oro-facial status of a group of 17 CS patients from 15 families participating in the National Hospital Program for Clinical Research (PHRC) 2005 « Clinical and molecular study of Cockayne syndrome ». All patients were examined by two investigators using the Diagnosing Dental Defects Database (D[4]/phenodent) record form.

Results: Various oro-facial and dental anomalies were found: retrognathia; micrognathia; high- arched narrow palate; tooth crowding; hypodontia (missing permanent lateral incisor, second premolars or molars), screwdriver shaped incisors, microdontia, radiculomegaly, and enamel hypoplasia. Eruption was usually normal. Dental caries was associated with enamel defects, a high sugar/carbohydrate soft food diet, poor oral hygiene and dry mouth. Cephalometric analysis revealed mid-face hypoplasia, a small retroposed mandible and hypo-development of the skull.

Conclusion: CS patients may have associated oro-dental features, some of which may be more frequent in CS children - some of them being described for the first time in this paper (agenesis of second permanent molars and radiculomegaly). The high susceptibility to rampant caries is related to a combination of factors as well as enamel developmental defects. Specific attention to these anomalies may contribute to diagnosis and help plan management.

Figure 1

Oro-dental features encountered in patients presenting with Cockayne syndrome(see also Table 1). Anomalies of tooth number (a) - three congenitally missing second permanent molars (teeth 17, 37, 47) and the lower inferior left premolar (35) (arrow) in patient 10; tooth shape (b) - screwdriver shape incisors (teeth 11, 21 in patient 15); (c) hyper developed cingulum on the permanent upper lateral incisors (patient 12); tooth size (d) - permanent dentition with a microdont conical upper left lateral incisor (arrow) (tooth 22 in patient 8; the 12 is congenitally missing); (e) with microdontia in the primary dentition (patient 4, notice the diastemata separating the smaller primary teeth); (a) taurodontic upper permanent first molars in patient 10; radiculomegaly of canines, premolars and molars (f,g, patient 16) – (i) tooth structure with enamel hypoplasia (h in patient 2, i in patient 6) in the primary dentition. Dental plaque and biofilm subsequent to poor oral hygiene as well as gingivitis were seen in patient 11 (j). Dental crowding was visible in (k) for patient 17. ((a) patient 10; (b) patient 15; (c) patient 12; (d) patient 8; (e) patient 4; (f;g) patient 16; (h) patient 2; (i) patient 6; (j) patient 11; (k) patient 17).