Dentinogenesis imperfecta

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Dentinogenesis imperfecta is a disorder of tooth development. This condition causes the teeth to be discolored (most often a blue-gray or yellow-brown color) and translucent. 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.

Researchers have described three types of dentinogenesis imperfecta with similar dental abnormalities. Type I occurs in people who have osteogenesis imperfecta, a genetic condition in which bones are brittle and easily broken. Dentinogenesis imperfecta type II and type III usually occur in people without other inherited disorders. A few older individuals with type II have had progressive high-frequency hearing loss in addition to dental abnormalities, but it is not known whether this hearing loss is related to dentinogenesis imperfecta.

Some researchers believe that dentinogenesis imperfecta type II and type III, along with a condition called dentin dysplasia type II, are actually forms of a single disorder. The signs and symptoms of dentin dysplasia type II are very similar to those of dentinogenesis imperfecta. However, dentin dysplasia type II affects the primary teeth much more than the permanent teeth.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Mutations in the DSPP gene have been identified in people with dentinogenesis imperfecta type II and type III. Mutations in this gene are also responsible for dentin dysplasia type II. Dentinogenesis imperfecta type I occurs as part of osteogenesis imperfecta, which is caused by mutations in one of several other genes (most often the COL1A1 or COL1A2 genes).

The DSPP gene provides instructions for making two 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. DSPP gene mutations alter the proteins made 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. It is unclear whether DSPP gene mutations are related to the hearing loss found in a few older individuals with dentinogenesis imperfecta type II.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

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

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormality of the dental root · Very frequent (99-80%)

An abnormality of the dental root.

Obliteration of the pulp chamber · Very frequent (99-80%)

Mineralized substance filling the entire dental pulp space.

Abnormality of dentin · Frequent (79-30%)

Any abnormality of dentin.

Abnormality of the dental pulp · Frequent (79-30%)

An abnormality of the dental pulp.

Fragile teeth · Frequent (79-30%)

A tendency of teeth to fracture as manifested by a history of repeated fracture of the dental enamel without adequate trauma.

Generalized hypoplasia of dental enamel · Frequent (79-30%)

A generalized form of developmental hypoplasia of the dental enamel.

Grayish enamel · Frequent (79-30%)

A gray discoloration of the dental enamel.

Hypocalcification of dental enamel · Frequent (79-30%)

A form of hypomineralization of enamel characterized by reduced calcification.

Joint hypermobility · Frequent (79-30%)

The capability that a joint (or a group of joints) has to move, passively and/or actively, beyond normal limits along physiological axes.

Odontodysplasia · Frequent (79-30%)

The diagnosis odontodysplasia requires clinical and radiological exams, in which unusually large pulp chambers and large pulp room chambers with thin enamel and dentin are visible. It may affect either a single tooth or several teeth. The term regional odontodysplasia is used if several teeth are affected. It affects the deciduous and permanent dentitions in the maxilla, the mandible or both, although the maxilla is more frequently involved. A type of dental dysplasia occurring in dentinogenesis imperfecta in which the pulp chambers are enlarged and there is a reduced amount of coronal dentin.

Yellow-brown discoloration of the teeth · Frequent (79-30%)

Bruising susceptibility · Occasional (29-5%)

An ecchymosis (bruise) refers to the skin discoloration caused by the escape of blood into the tissues from ruptured blood vessels. This term refers to an abnormally increased susceptibility to bruising. The corresponding phenotypic abnormality is generally elicited on medical history as a report of frequent ecchymoses or bruising without adequate trauma.

Hyperextensibility at elbow · Occasional (29-5%)

The ability of the elbow joint to move beyond its normal range of motion.

Knee joint hypermobility · Occasional (29-5%)

The ability of the knee to move past its normal range of motion, (knee hyperextension is greater than 10 degrees).

Other findings in the same source

From: Orphanet

Additional reported features include Persistence of primary teeth (Occasional (29-5%)); Selective tooth agenesis (Occasional (29-5%)); Short dental roots (Occasional (29-5%)); Finger joint hypermobility (Occasional (29-5%)); Blue sclerae (Very rare (<4-1%)); Hearing impairment (Very rare (<4-1%)); Prolonged bleeding time (Very rare (<4-1%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Dentinogenesis imperfecta is Dentistry, with a dentist / relevant dental specialist as the relevant type of clinician. Dentist / Relevant dental specialist; paediatric services for children as appropriate.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which teeth, gum tissues or oral structures are affected?
• What is the purpose of any proposed dental imaging or procedure?
• What oral-care routine is suitable while the problem is being treated?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Dentinogenesis imperfecta. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.