Gnathodiaphyseal dysplasia (GDD) is a rare autosomal dominant disorder characterized by florid osseous dysplasia of the jaws, bone fragility, and diaphyseal cortical thickening and bowing of long bones. We present a family with previously undiagnosed GDD. The disorder was identified by the characteristic gnathic and skeletal manifestations in the father. Clinical and radiologic examination of the patient's son also revealed the characteristic features of GDD. Gene sequencing revealed a novel mutation (c. 1067 G>A, p. Cys356 Tyr) in the ANO5 gene, which is causative for GDD. This mutation was predicted to be detrimental by computational analyses and by structural modeling of the protein. The implications for recognition and management of this disease are discussed.