Fragile X syndrome: panoramic radiographic evaluation of dental anomalies, dental mineralization stage, and mandibular angle

ABSTRACT Fragile X syndrome (FXS) is a disorder linked to the chromosome X long arm (Xq27.3), which is identified by a constriction named fragile site. It determines various changes, such as behavioral or emotional problems, learning difficulties, and intellectual disabilities. Craniofacial abnormalities such as elongated and narrow face, prominent forehead, broad nose, large and prominent ear pavilions, strabismus, and myopia are frequent characteristics. Regarding the oral aspects, deep and high-arched palate, mandibular prognathism, and malocclusion are also observed. Objective: The purpose of this study was to evaluate the dental radiographic characteristics as described in 40 records of patients with panoramic radiography. Material and Methods: The patients were in the range of 6–17 years old, and were divided into two groups (20 subjects who were compatible with the normality standard and 20 individuals diagnosed with the FXS), which were matched for gender and age. Analysis of the panoramic radiographic examination involved the evaluation of dental mineralization stage, mandibular angle size, and presence of dental anomalies in both deciduous and permanent dentitions. Results: The results of radiographic evaluation demonstrated that the chronology of tooth eruption of all third and second lower molars is anticipated in individuals with FXS (p<0.05). In this group, supernumerary deciduous teeth (2.83%), giroversion of permanent teeth (2.31%), and partial anodontia (1.82%) were the most frequent dental anomalies. In addition, an increase was observed in the mandibular angle size in the FXS group (p<0.05). Conclusion: We conclude that knowledge of dental radiographic changes is of great importance for dental surgeons to plan the treatment of these individuals.

Fragile X syndrome: clinical, electroencephalographic and neuroimaging characteristics

We studied 11 patients (9 males) with cytogenetic diagnosis of fragile X syndrome (FXS) with the purpose of investigating the neural circuitry involved in this condition. The ages ranged from 8 to 19. All the individuals presented large ears, elongated faces and autistic features. Ten patients had severe mental retardation. Attention disorder was found in 10 individuals. Electroencephalographic recordings were abnormal in 6 of 10 patients examined, showing focal epileptiform discharges predominantly in frontal and parietal areas. All patients underwent magnetic resonance imaging studies which were abnormal in 8 of them. The most important abnormalities were reduction of the cerebellar vermis and enlargement of the IV ventricle. Single photon emission computerized tomography (SPECT) was performed in 7 patients and was abnormal in all of them, the most frequent finding being a hypoperfusion of the inferior portions of the frontal lobes. Based on the clinical picture, neuropsychological findings and functional and structural imaging studies we suggest that FXS presents with a dysfunction involving a large area of the central nervous system: cerebellum - basal frontal regions - parietal lobes. The literature points to a disturbance involving the same neural circuitry in patients with austin.