Small Patella Syndrome via the TBX4 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
8595 TBX4 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8595TBX481479 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. If the Sanger option is selected, CNV detection may be ordered through Test #600.

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

For Reflex to PGxome pricing click here.

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 14 days on average for STAT orders.

Once a specimen has started the testing process in our lab, the most accurate prediction of TAT will be displayed in the myPrevent portal as an Estimated Report Date (ERD) range. We calculate the ERD for each specimen as testing progresses; therefore the ERD range may differ from our published average TAT. View more about turnaround times here.

Targeted Testing

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


Genetic Counselors


Clinical Features and Genetics

Clinical Features

Small patella syndrome (OMIM#147891; aka Scott-Taor syndrome), is a rare skeletal dysplasia affecting skeletal structures of the lower limb and the pelvis. It is characterized by patellar aplasia or hypoplasia and by anomalies of the pelvis and feet, including disrupted ossification of the ischia and inferior pubic rami. (Bongers et al. Am J Hum Genet 74:1239–1248, 2004).


Small patella syndrome is inherited in an autosomal dominant manner. It is caused by variants in the TBX4 gene, which encodes a transcription factor with a strongly conserved DNA-binding T-box domain that plays a crucial role in lower limb development (Bongers et al. Am J Hum Genet 74:1239-1248, 2004). A variety of variants including missense, nonsense, splice-site, frameshift, and gross deletion/insertion in TBX4 have been reported to cause this condition.

Clinical Sensitivity - Sequencing with CNV PGxome

Small patella syndrome (SPS) is a rare condition. Series of SPS patients screened for TBX4 variants have not been described in the literature. Bongers et al (2004) detected heterozygous TBX4 variants in all five studied SPS families and one of two sporadic cases.

Testing Strategy

This test provides full coverage of all coding exons of the TBX4 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.

Since this test is performed using exome capture probes, a reflex to any of our exome based tests is available (PGxome, PGxome Custom Panels).

Indications for Test

Candidates for this test are patients with clinical features consistent with small patella syndrome and family members of patients who have known TBX4 variants.


Official Gene Symbol OMIM ID
TBX4 601719
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Small patella syndrome AD 147891


  • Bongers, E. M., (2004). "Mutations in the human TBX4 gene cause small patella syndrome." Am J Hum Genet 74(6): 1239-48. PubMed ID: 15106123


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.

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

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View Ordering Instructions

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.

Total Price: $
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