Genotype and malocclusion in patients with osteogenesis imperfecta

OBJECTS

To investigate the relationship between genotype and severity of malocclusion in osteogenesis imperfecta (OI).

SETTING AND SAMPLE POPULATION

A total of 49 patients participated in this cross-sectional study (age range: 5-19 years; 28 females; diagnoses: OI type I, N = 7; OI type III, N = 11; OI type IV, N = 27; OI type V, N = 2; OI type VI, N = 2).

MATERIALS AND METHODS

Sequence analysis of COL1A1/COL1A2 and other OI-related genes was compared to the Peer Assessment Rating (PAR), an index reflecting the severity of malocclusion.

RESULTS

The mutation spectrum was as follows: COL1A1, N = 22; COL1A2, N = 22, IFITM5, N = 2; SERPINF1, N = 2; no mutation detected, N = 1). Compared to patients with COL1A1 mutations, patients with COL1A2 mutations had significantly higher scores for total PAR, anterior cross-bite, anterior open bite and anteroposterior buccal occlusion. Males with COL1A2 mutations had significantly higher total PAR scores than females (median 36 vs 30, P = .047, Mann-Whitney test). Exploratory correlation between age and buccal vertical occlusion was noted in patients with COL1A2 mutations (Spearman correlation: r = .46, P = .03, power = .50). Two patients with OI type V (caused by IFITM5 mutations) had total PAR scores of 44 and 21. Both patients scored high for "segment." Patients with OI type VI (due to SERPINF1 mutations) scored similar to OI type V for "centreline." Considerable difference was observed in the total PAR score between the 2 patients with OI type VI. They had total PAR of 43 and 2.

CONCLUSION

Type of disease-causing mutation affects the severity of malocclusion in individuals with OI.

Craniofacial and Dental Defects in the Col1a1Jrt/+ Mouse Model of Osteogenesis Imperfecta

Certain mutations in the COL1A1 and COL1A2 genes produce clinical symptoms of both osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS) that include abnormal craniofacial growth, dental malocclusion, and dentinogenesis imperfecta. A mouse model (Col1a1(Jrt)/+) was recently developed that had a skeletal phenotype and other features consistent with moderate-to-severe OI and also with EDS. The craniofacial phenotype of 4- and 20-wk-old Col1a1(Jrt)/+ mice and wild-type littermates was assessed by micro-computed tomography (µCT) and morphometry. Teeth and the periodontal ligament compartment were analyzed by µCT, light microscopy/histomorphometry, and electron microscopy. Over time, at 20 wk, Col1a1(Jrt)/+ mice developed smaller heads, a shortened anterior cranial base, class III occlusion, and a mandibular side shift with shorter morphology in the masticatory region (maxilla and mandible). Col1a1(Jrt)/+ mice also had changes in the periodontal compartment and abnormalities in the dentin matrix and mineralization. These findings validate Col1a1(Jrt)/+ mice as a model for OI and EDS in humans.