Dentinogenesis Imperfecta Type 2

Dentinogenesis imperfecta type 2 (DGI-2) is a rare, severe form of dentinogenesis imperfecta (DGI, see this term) and is characterized by weakness and discoloration of all teeth.

Epidemiology

Prevalence of DGI-2 is reported to be 1/6,000 to 1/8,000.

Clinical description

The dental features of DGI-2 are typically bulbous crowns with marked cervical constriction along with amber translucent discoloration and tooth attrition. Roots are generally short and constricted. Both primary and permanent teeth present pulp obliteration. Patients with this form of DGI have no normal teeth. Sensorineural hearing loss has also been found in some patients.

Etiology

DGI-2 is caused by mutations in the DSPP gene (4q21.3) coding for dentin sialophosphoprotein, a precursor for dentin sialoprotein and dentin phosphoprotein which are involved in dentinogenesis.

Diagnostic methods

Diagnosis is based on history, clinical examination and radiographic features. Molecular genetic testing can be used to confirm the diagnosis.

Differential diagnosis

Differential diagnoses include conditions that may have similar clinical or radiographic features to DGI such as osteogenesis imperfecta and dentin dysplasia (see this term). The clinical symptoms may be mistaken for hypocalcified amelogenesis imperfecta, congenital erythropoietic porphyria, conditions leading to early tooth loss (Kostmann syndrome, cyclic neutropenia, Chediak-Hegashi syndrome, Langerhans cell histiocytosis, Papillon-Lefèvre syndrome), vitamin D-resistant rickets (see these terms), as well as permanent teeth discoloration due to tetracyclines, and vitamin D-dependent rickets. It is important to investigate for a history of bone fractures with minimal trauma, hearing loss and to check for blue sclerae to rule out osteogenesis imperfecta (see this term).

Genetic counseling

DGI-2 follows an autosomal dominant pattern of inheritance. There is therefore a 50% risk that a child born to an affected parent will have the condition.

Management and treatment

Protection of primary and then permanent teeth with preformed pediatric crowns, cast occlusal onlays on first permanent molars and eventually premolars, may help to minimize tooth wear and maintain the occlusal vertical dimension. Obliteration of pulp spaces in teeth that develop abscesses makes endodontic treatment extremely difficult if not impossible. Appropriate care makes it possible to achieve good esthetic appearance and functional performance. The replacement of teeth might be considered with dentures or implants.

Prognosis

Prognosis depends primarily on the age of diagnosis and the quality of management. Early diagnosis and regular dental care cannot always prevent premature tooth loss.