Using DNA to Predict Scoliosis

Six million people (estimate from the National Scoliosis Foundation) have scoliosis in one form or another. The primary age range for onset of idiopathic scoliosis is 10-15, occurring equally in both genders but females are eight times more likely to progress to curve magnitude that requires intervention.

Idiopathic or degenerative scoliosis is the cause of:

  • 600,000 physician visits annually
  • 30,000 children put in braces
  • 38,000 spinal fusion surgeries

(Source: National Scoliosis Foundation)

Scoliosis is also an inherited disease.

Figure 1

Last week, Axial Biotech presented data at the Scoliosis Research Society (SRS) meeting in Salt Lake City that could and should dramatically change the way that scoliosis is diagnosed and treated in the United States. After four years of development, testing DNA samples from more than 9,000 patients, tracking billions of genotypes and making trillions of calculations, the company announced that it has found the specific, genetic markers for scoliosis.

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Why is this significant? It is significant because it will enable physicians to use a simple test to accurately identify—before taking dozens of X-rays and prescribing extensive bracing—which patients will progress to the severe stage. Not only will this save millions of dollars, but it also will change the treatment paradigm to one with earlier and presumably more successful intervention.

Figure 2

Axial Biotech is commercializing the test for Adolescent Idiopathic Scoliosis (AIS) under the brand name ScoliScore™. Johnson & Johnson’s DePuy Spine is distributing the test.

Presently, AIS is diagnosed and then treated almost entirely by a time lapse series of x-rays which form the basis for measuring the patient’s curve magnitude (the only caveat being that brace treatment is thought to be effective only in patients who are still growing).

A typical case would be a young patient whose parents have noticed excessive spine curvature or the patient complaining of back pain. The physician takes a series of X-rays and measurements and if AIS is diagnosed, begins a treatment plan as follows:

  • Observe (via X-ray) curves less than 30°
  • Brace curves in the 30°–40° range
  • Perform surgery if curves exceed 40°

Notice that each decision point rests on a 10° increment—including between observation and major spinal surgery. Well, 10° is also the commonly discussed margin of error for measuring scoliotic curves.

Then there is the added issue of rapidly growing adolescents. A 13-year-old child can suddenly hit a growth phase and go from 16°–26° literally overnight.

How accurate is the Axial Biotech ScoliScore? Based on data from over 6,500 AIS patients:

  • Sensitivity of ScoliScore is 90% (87–93)
  • Specificity of ScoliScore is 88% (86–90)
  • Sensitivity and specificity were confirmed in two clinical trials, with each trial including over 400 scoliosis patients

The Negative Predictive Value in the intended use population is 93%–98% (89–100), as confirmed by the clinical trials.

Figure 3

Dr. Ken Ward, Chief Scientific Officer for Axial Biotech said this: “These landmark studies have provided researchers with greater insights into the genetic markers associated with spinal curve progression. The AIS Prognostic Test, which can determine whether a child has a mild or more severe likelihood of curve progression, at the very first presentation of symptoms, will provide comfort to thousands of children and their families every year.

Dr. Jim Ogilvie, Axial Biotech’s Chief Medical Consultant said, “I believe that the use of DNA-based testing to determine the likelihood of disease progression will initiate a new era of improvements in spine health. From a clinical standpoint, this test delivers the promise of personalized medicine to spine surgeons who will now have the ability to accurately determine the likely disease progression for an individual AIS patient, and they can make evidence-based recommendations for patient-specific treatment options.”

At the same time that Axial Biotech presented its data at the Scoliosis Research Society annual meeting, it was also crunching the data on 9,000 patients to identify genetic factors that initially cause idiopathic scoliosis. That, in turn, may allow both a better understanding of the specific biology for AIS and creation of molecular-based treatments for scoliosis patients.

DePuy Spine, a division of Johnson & Johnson Corporation, is the distributor for Axial’s ScoliScore™ test.

Axial Biotech, incidentally, is accredited by the College of American Pathologists (CAP) and is certified to comply with the Clinical Laboratory Improvement Amendments (CLIA).

Almost a decade ago, the human genome was sequenced and the press was filled with stories about how we would eventually alter many aspects of clinical practice through DNA testing. By understanding the mechanisms of disease, researchers and physicians will have new, more powerful but less expensive drugs and therapeutic procedures.

This announcement at the SRS meeting by Axial Biotech brings the promise of DNA testing from the dream to reality.

Written by Robin Young, CFA