Recurrent femoral shaft fractures in a child with gnathodiaphyseal dysplasia: a case report

Craniofacial disorders and dysplasias: Molecular, clinical, and management perspectives

There is a wide spectrum of craniofacial bone disorders and dysplasias because embryological development of the craniofacial region is complex. Classification of craniofacial bone disorders and dysplasias is also complex because they exhibit complex clinical, pathological, and molecular heterogeneity. Most craniofacial disorders and dysplasias are rare but they present an array of phenotypes that functionally impact the orofacial complex. Management of craniofacial disorders is a multidisciplinary approach that involves the collaborative efforts of multiple professionals. This review provides an overview of the complexity of craniofacial disorders and dysplasias from molecular, clinical, and management perspectives.

Ano5 modulates calcium signaling during bone homeostasis in gnathodiaphyseal dysplasia

ANO5 encodes transmembrane protein 16E (TMEM16E), an intracellular calcium-activated chloride channel in the endoplasmic reticulum. Mutations in ANO5 are associated with gnathodiaphyseal dysplasia (GDD), a skeletal disorder causing the jaw deformity and long bone fractures. However, the coordinated mechanism by which ANO5 mediates bone homeostasis in GDD remains poorly defined. Here, we show that ablation of Ano5 reduced intracellular calcium transients, leading to defects in osteogenesis and osteoclastogenesis and thus bone dysplasia. We found a causative de novo ANO5 frameshift insertion mutation (p.L370_A371insDYWRLNSTCL) in a GDD family with osteopenia, accompanied by a decrease in TMEM16E expression and impaired RANKL-induced intracellular calcium ([Ca²⁺]_i) oscillations in osteoclasts. Moreover, using Ano5 knockout (KO) mice, we found that they exhibited low bone volume, abnormal calcium deposits, and defective osteoblast and osteoclast differentiation. We also showed that Ano5 deletion in mice significantly diminished [Ca²⁺]_i oscillations in both osteoblasts and osteoclasts, which resulted in reduced WNT/β-Catenin and RANKL-NFATc1 signaling, respectively. Osteoanabolic treatment of parathyroid hormone was effective in enhancing bone strength in Ano5 KO mice. Consequently, these data demonstrate that Ano5 positively modulates bone homeostasis via calcium signaling in GDD.

Surgical Treatment of Pathological Tibial Shaft Fracture in Adult Patient With Gnathodiaphyseal Dysplasia: A Case Report

CASE

Gnathodiaphyseal dysplasia is a generalized skeletal syndrome characterized by frequent bone fractures in childhood, sclerosis and bowing of tubular bones, and cemento-osseous lesions of the jawbones. We present the case of a 53-year-old man with gnathodiaphyseal dysplasia who presented with pathological fracture of the tibial shaft. Internal fixation with the Ender nail was successfully performed with 2 years of follow-up.

CONCLUSION

This is the first report describing the treatment of fracture in an adult patient with gnathodiaphyseal dysplasia. Internal fixation with the Ender nail was effective for the tubular bone with deformity. Callus formation was observed without delay.