A new study shows that the Scoliscore adolescent idiopathic scoliosis prognostic test, a DNA test to determine the likelihood of curve progression in children with mild adolescent idiopathic scoliosis, is 99% accurate in predicting which children are least likely to progress to a severe curve (Cobb Angle of 40 degrees or more)
Researchers analysed DNA samples and medical records of nearly 700 patients from over 100 clinical sites throughout the United States. Their findings appear in the 1 December, 2010 online edition of Spine.
“This study demonstrates that for the first time genetic factors can be used to accurately quantify the risk of scoliosis curve progression,” said Kenneth Ward , study co-author and chief scientific officer of Axial Biotech, the developer of the test and the laboratory that conducts the DNA analysis used in the Scoliscore test. “Physicians never had this kind of information before. Now that they do, physicians can better personalise treatment plans and provide peace of mind to patients and their families.”
When a child is diagnosed with mild adolescent idiopathic scoliosis, it is very difficult for physicians to predict if that curve will progress to a more severe form of the condition, which may require surgery or other treatments. The Scoliscore test, when combined with other radiographic and clinical information obtained at the time of diagnosis, is designed to help reduce that uncertainty, and may help patients reduce the need for repeated doctor visits, physical examinations and years of frequent X-rays.
Researchers studied 697 Caucasian patients between the ages of nine and 13 who had mild, moderate or severe AIS, as documented by medical records. DNA from their saliva was analysed using the Scoliscore test, which produces a score of 1 to 200 indicating a patient’s individual risk for developing a spinal curve of more than 40 degrees. A score of 50 or less is classified as low risk, 51 to 180 is intermediate risk and 181 to 200 is high risk. The score is calculated based on 53 genetic markers previously identified as being associated with scoliosis progression and the patient’s current spinal curve or Cobb Angle.
The study found the Scoliscore test had a 99% accuracy rate in identifying low-risk patients, those least likely to progress to a curve of 40 degrees or more. Study authors advise that although the test is accurate for patients who score in the intermediate- or high-risk range, they should be followed closely by a scoliosis specialist since the study was designed to determine negative predictive value rather than likelihood of progression.
According to the National Scoliosis Foundation, scoliosis affects about 7 million people mostly children, but studies show that only 1 to 4% of patients diagnosed with scoliosis experience curve progression severe enough to warrant surgery (curves of 45 degrees or more). However, most children with mild AIS (curves of 25 degrees or less) are regularly monitored for possible progression until they stop growing. This generally means X-rays and physical examinations every four to six months over a period of several years. In some cases, children wear a brace in an attempt to slow or stop possible curve progression.
“Scoliosis can be a devastating diagnosis for children and their families. They all fear the worst. Now we can reduce that fear for most patients since most patients are at low risk for severe curve progression,” said Harry L Shufflebarger, director of the Division of Pediatric Spine Surgery at Miami Children’s Hospital, a scoliosis specialist who helped recruit patients for the study, but was not involved in analysing the study results. “It is important however to remember, that while the Scoliscore test gives us important information, the results of the test must be interpreted in the context of all other clinical and diagnostic information when developing management plans and setting expectations for patients.”
Though suspected for many years, only recently have studies demonstrated that adolescent idiopathic scoliosis has a strong genetic component. Building on this knowledge, researchers reviewed the medical and DNA records of more than 9,500 scoliosis patients and their family members. This led to the development of the Scoliscore test, the first commercially available genetic test for a spinal deformity. It is intended for Caucasian children between age nine and 13 diagnosed with mild adolescent idiopathic scoliosis (10°−25° Cobb Angle).
Currently, the test is offered only to Caucasian patients because despite aggressive targeted recruitment efforts of patients of all races for inclusion in the study, sufficient sample sizes were only obtained for Caucasian children. Unlike other genetic tests, the Scoliscore test helps predict the risk of progression to a more severe curve once adolescent idiopathic scoliosis is diagnosed. It does not predict an individual’s susceptibility to inherit the condition, or the final outcome of a patient’s progression.