Gnathodiaphyseal Dysplasia, or GDD, is a genetic disease caused by a mutation in GDD1 or the Anoctamin 5 (ANO5) gene. GDD1 is responsible for making the Anoctamin-5 protein, and missense point mutations in this gene are responsible for the symptoms of GDD. This protein belongs to the Anoctamins family, which act as chloride channels. Although the gene itself is inherited in an autosomal-dominant pattern, the exact biochemical pathways of the disorder are still unknown (Tsutsumi et al., 2004). GDD was mistakenly considered a variant of Osteogenesis Imperfecta (OI) until it was first recognized as a separate entity in 1969 by Alasaka et al. (Akasaka et al., 1969). In 2001 Riminucci et al. officially proposed the term Gnathodiaphyseal Dysplasia (Riminucci et al., 2001). In 2003–04, the chromosome and then the gene responsible for this disorder was discovered through genetic studies and was termed GDD1 or Anoctamin 5 gene (ANO5) (Tsutsumi et al., 2003; Tsutsumi et al., 2004). GDD is incredibly rare, occurring in less than 1000 people in the United States. The worldwide prevalence is still unknown.

This disorder affects the musculoskeletal system and has 2 phenotypical variants, which can occur independently or co-exist. The skeletal variant exhibits reduced bone-mineral density (osteopenia), bone fragility, and bowing of the long bones. The cortex of the long bone is abnormally hard leading to diaphyseal sclerosis. Jawbone affection may present as infection, osteonecrosis of the jaw and cemento-osseous lesions or dysplasia (COD). The muscular variant exhibits myopathy, rhabdomyolysis, muscle hypertrophy and hyperCKemia.

Symptoms may start as early as infancy and patients usually present with frequent pathological fractures with little or no precipitating trauma, and bone or muscle aches (myalgia) that could be refractory to treatment, impacting the quality of life and requiring pain management. Muscle weakness may escalate to paresis or even paralysis, and unexplained elevation of creatinine kinase levels can be seen. Facial symptoms include facial skeletal deformity, malocclusion, or predisposition to jaw infections with purulent drainage of the jawbone. Affected persons also may present with receding gums or loose teeth.

Due to the rarity of this disorder, there have been very few case reports describing this disorder and the surgical procedures performed on patients with GDD, especially involving the jaws. The scarcity of literature likely stems from the notable bone fragility which may lead surgeons to opt for non-surgical treatment, or to avoid reporting any complications encountered.

This case report focuses on a single patient with Gnathodiaphyseal Dysplasia with Angle Class III malocclusion.