Case report: a giant cell-rich gnathic bone lesion in a child with pycnodysostosis

Pycnodysostosis is a skeletal dysplasia characterized by short stature, generalized osteosclerosis, acro-osteolysis, and recognizable facial features. Oral manifestations are commonly described and include a high-arched palate with dental crowding and malocclusion, hypoplastic enamel, and retained deciduous teeth with impacted permanent teeth, and there is an increased risk of developing osteomyelitis of the jaw. We report here the history of a 9-year-old male with the typical facial and skeletal phenotype of pycnodysostosis but novel oral features. He presented with bilateral progressive facial swelling, which caused functional impairment with chewing and contributed to his severe obstructive sleep apnea (OSA). The severity of his OSA required surgical intervention, and the lesions were resected. Extensive bone remodeling and replacement by fibrous tissue were noted on submucosal dissection, and bilateral subtotal maxillectomies were required. The histopathology of the biopsied lesion was consistent with a giant cell-rich lesion. Genetic testing identified a pathogenic homozygous variant in the CTSK gene, c.953G > A, p. (Cys318Tyr). The proband had a good postsurgical response with sustained improvement in his sleep OSA. We present here the history and clinical characteristics of a patient with typical features of pycnodysostosis and an unusual presentation and histopathology of gnathic bone lesions. This report adds to the body of literature on this rare condition and also highlights the finding of giant cell-rich lesions of the gnathic bones. Giant cell-rich lesions in pycnodysostosis have previously been reported in two cases in the literature. While there is not enough evidence to support a certain association with pycnodysostosis, it is prudent to consider regular oral dental reviews in affected individuals to identify pathology early and avoid such life-threatening complications.

The tricho-rhino-phalangeal syndrome: oral manifestations and management

Tricho-rhino-phalangeal Syndrome (TRPS) is a rare inherited dysplasia affecting hair, nasal structure and fingers. A literature review indicated that since first described, three types of manifestations have been identified. A Table summarising the oral manifestations demonstrates the variety of presentations. A South African male child presented with the syndrome and was found to show premature eruption of permanent teeth, a finding that has not been previously reported. His oro-facial manifestations also included malaligned and unerupted crowded teeth, bulbosity of the nasal tip and an elongated philtrum and evidence of mild intellectual impairment. A protocol has been developed to guide the future management of these cases.

Mutation update for the CSB/ERCC6 and CSA/ERCC8 genes involved in Cockayne syndrome

Cockayne syndrome is an autosomal recessive multisystem disorder characterized principally by neurological and sensory impairment, cachectic dwarfism, and photosensitivity. This rare disease is linked to mutations in the CSB/ERCC6 and CSA/ERCC8 genes encoding proteins involved in the transcription-coupled DNA repair pathway. The clinical spectrum of Cockayne syndrome encompasses a wide range of severity from severe prenatal forms to mild and late-onset presentations. We have reviewed the 45 published mutations in CSA and CSB to date and we report 43 new mutations in these genes together with the corresponding clinical data. Among the 84 reported kindreds, 52 (62%) have mutations in the CSB gene. Many types of mutations are scattered along the whole coding sequence of both genes, but clusters of missense mutations can be recognized and highlight the role of particular motifs in the proteins. Genotype-phenotype correlation hypotheses are considered with regard to these new molecular and clinical data. Additional cases of molecular prenatal diagnosis are reported and the strategy for prenatal testing is discussed. Two web-based locus-specific databases have been created to list all identified variants and to allow the inclusion of future reports (www.umd.be/CSA/ and www.umd.be/CSB/).

Freeman-Sheldon syndrome: dental and orthodontic implications

The manifestations of the Freeman-Sheldon syndrome (FSS) in four members of a South African family of Xhosa stock have been documented. Orofacial manifestations are a major syndromic component and warrant early, specialized orthodontic intervention. Our protocol for dental management is outlined and suggestions for holistic oro-dental care are provided.