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Dentinogenesis Imperfecta (DGI) and Dentin Dysplasia (DD) via the DSPP Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
9971 DSPP 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
9971DSPP81479 81479,81479 $890 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing backbone).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing backbone).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

Turnaround Time

18 days on average for standard orders or 13 days on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Megan Piazza, PhD, FACMG

Clinical Features and Genetics

Clinical Features

Inherited dentin malformations are classified into three types of dentinogenesis imperfecta (DGI) and two types of dentin dysplasia (DD) (Shields et al. Arch Oral Biol 18:543-553, 1973). DGI-I (OMIM 166240): Syndromic DGI. This includes individuals afflicted with osteogenesis imperfecta. Both deciduous and permanent teeth are discolored (grey-yellowish) and worn. Pulpal obliteration is apparent both prior to and upon tooth eruption. Expressivity is variable, even within a single patient, ranging from total obliteration to normal-appearing dentin.

DGI-II (OMIM 125490): Similar to DGI-I, but penetrance is almost complete and expressivity is consistent.

DGI-III (OMIM 125500): Phenotypic variant of DGI-II, but with large pulp chambers resembling shell teeth in deciduous teeth.

DD-I (OMIM 125400): Deciduous and permanent teeth appear normal but radiologically show short roots with crescent-shaped pulpal remnant parallel to the cemento-enamel junction in the permanent teeth and total pulpal obliteration in the deciduous teeth. Non-carious teeth usually show numerous periapical radiolucencies.

DD-II (OMIM 125420): Deciduous teeth have features of DGI-II. The permanent teeth are normal, but pulp cavities show a thistle-tube deformity and commonly contain pulp stones.

Genetics

DGI (opalescent dentin) is the most common heritable dentin disease. In the United States, the prevalence is estimated between 1:6,000 and 1:8,000; DGI-III may be even more predominant in the “Brandywine isolate” population of mixed Caucasian, Black, and Amerindian ancestry (see Acevedo et al. Cells Tissues Organs 189:230-236, 2009). Variants in the DSPP gene are known to cause DGI-II (Xiao et al. Nat Genet 27:201-204, 2001; Malmgren et al. Hum Genet 114:491-498, 2004), DGI-III (Kim et al. Hum Genet 116:186-191, 2005), and DD-II (Rajpar et al. Hum Mol Genet 11:2559-2565, 2002). Variants in DSPP exhibit an autosomal dominant mode of inheritance. DSPP encodes a 940 amino-acid polypeptide produced in odontoblasts that is cleaved into dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) (MacDougall et al. J Biol Chem 272:835-842, 1997). DSP and DPP are noncollagenous matrix proteins that play a crucial role in dentinogenesis: most causative variants have been reported in the DSP-coding region (mainly in exons 2-3). Causative variants are distributed rather evenly among missense, nonsense, splicing, and small deletions. The DGI phenotype is also a variable feature in many other syndromes including osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS), Goldblatt syndrome (OMIM 184260), and Schimke immuno-osseous dysplasia (SIOD, OMIM 242900).

Clinical Sensitivity - Sequencing with CNV PGxome

No disease-causing variants outside of the DSPP gene have been identified for nonsyndromic DGI or DD.

Testing Strategy

This test provides full coverage of all coding exons of the DSPP gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Exon 5 of the gene has a large repeat element; sequencing covers the 5’ portion of the coding sequence up to the repeat and the 3’ portion after the repeat along with ~10 bp of flanking non-coding DNA on either side of this exon.

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).

Indications for Test

Patients with symptoms of DGI / DD, and patients with a history of early tooth loss.

Gene

Official Gene Symbol OMIM ID
DSPP 125485
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Citations

  • Acevedo, A. C., et.al. (2009). "Phenotype characterization and DSPP mutational analysis of three Brazilian dentinogenesis imperfecta type II families." Cells Tissues Organs 189(1-4): 230-6. PubMed ID: 18797159
  • Dong, J., et.al. (2005). "Dentin phosphoprotein compound mutation in dentin sialophosphoprotein causes dentinogenesis imperfecta type III." Am J Med Genet A 132A(3): 305-9. PubMed ID: 15690376
  • Kim, J. W., et.al. (2005). "Mutational hot spot in the DSPP gene causing dentinogenesis imperfecta type II." Hum Genet 116(3): 186-91. PubMed ID: 15592686
  • MacDougall, M., et.al. (1997). "Dentin phosphoprotein and dentin sialoprotein are cleavage products expressed from a single transcript coded by a gene on human chromosome 4. Dentin phosphoprotein DNA sequence determination." J Biol Chem 272(2): 835-42. PubMed ID: 8995371
  • Malmgren, B., et.al. (2004). "Clinical, histopathologic, and genetic investigation in two large families with dentinogenesis imperfecta type II." Hum Genet 114(5): 491-8. PubMed ID: 14758537
  • Rajpar, M. H., et.al. (2002). "Mutation of the signal peptide region of the bicistronic gene DSPP affects translocation to the endoplasmic reticulum and results in defective dentine biomineralization." Hum Mol Genet 11(21): 2559-65. PubMed ID: 12354781
  • Shields, E. D., et.al. (1973). "A proposed classification for heritable human dentine defects with a description of a new entity." Arch Oral Biol 18(4): 543-53. PubMed ID: 4516067
  • Xiao, S., et.al. (2001). "Dentinogenesis imperfecta 1 with or without progressive hearing loss is associated with distinct mutations in DSPP." Nat Genet 27(2): 201-4. PubMed ID: 11175790

Ordering/Specimens

Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page


Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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ORDER OPTIONS

View Ordering Instructions

1) Select Test Method (Backbone)


1) Select Test Type


2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
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