Dentinogenesis imperfecta type 3

Alternate names

Dentinogenesis imperfecta type III; Brandywine type dentinogenesis imperfecta; Dentinogenesis imperfecta Shields type 3 ; Dentinogenesis imperfecta, Shields type 3

Definition

Dentinogenesis imperfecta type 3 is a rare and severe form of dentinogenesis imperfecta, a condition that affects tooth development.

Epidemiology

Dentinogenesis imperfecta affects an estimated 1 in 6,000 to 8,000 people.

Cause

• Dentinogenesis imperfecta type 3 is caused by changes (mutations) in the DSPP gene.
• The DSPP gene provides instructions for making three proteins that are essential for normal tooth development.
• These proteins are involved in the formation of dentin, which is a bone-like substance that makes up the protective middle layer of each tooth.

Gene mutations

• Mutations in DSPP alter the proteins encoded from the gene, leading to the production of abnormally soft dentin.
• Teeth with defective dentin are discolored, weak, and more likely to decay and break.

Inheritance

Autosomal dominant pattern, a 50/50 chance.

• Dentinogenesis imperfecta type 3 is inherited in an autosomal dominant manner.
• This means that to be affected, a person only needs a change (mutation) in one copy of the responsible gene in each cell. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new (de novo) mutations in the gene. These cases occur in people with no history of the disorder in their family. A person with dentinogenesis imperfecta type 3 has a 50% chance with each pregnancy of passing along the altered gene to his or her child.

Signs and symptoms

• People affected by this condition generally have discolored (most often a blue-gray or yellow-brown color) and translucent teeth.
• Teeth are also weaker than normal, making them prone to rapid wear, breakage, and loss.
• These problems can affect both primary (baby) teeth and permanent teeth.

Diagnosis

Radiographs of the deciduous dentition show very large pulp chambers and root canals, at least during the first few years, although they may become reduced in size with age. The permanent teeth have pulpal spaces that are either smaller than normal or completely obliterated. Patients with Shields type III, or the Brandywine type, do not have stigmata of osteogenesis imperfecta.

Treatment

Treatment is usually focused on protecting primary (baby) and then permanent teeth with preformed pediatric crowns and other interventions. The replacement of teeth might be considered in the future with dentures and/or implants.

NIH genetic and rare disease info

• NIH info on Dentinogenesis imperfecta type 3

Dentinogenesis imperfecta type 3 is a rare disease.

Dentinogenesis imperfecta type 3 Resources
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