Genetic testing for AIS
Encyclopedia
AIS genetic testing is the process of analyzing the DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 of a patient who has been diagnosed with Adolescent Idiopathic Scoliosis
Scoliosis
Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C" than a straight line...

 to determine his or her likelihood of progression to a severe spinal curve.

AIS is the most common pediatric spinal deformity and is defined as a lateral curvature of the spine
Vertebral column
In human anatomy, the vertebral column is a column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx. It is situated in the dorsal aspect of the torso, separated by intervertebral discs...

 of greater than 10 degrees with a rotational component and with no other etiologic explanation for spinal deformity, presenting in a child nine years of age or older. There can be many causes for spinal deformity, including congenital, neuromuscular, traumatic, and others. Idiopathic Scoliosis is that for which all other etiologic explanations have been ruled out.

Medical intervention for scoliosis depends on the degree of curve severity. Only approximately 4% of AIS patients will progress to the point where surgery is done. The majority of adolescents with idiopathic scoliosis are observed at regular intervals (usually between 4–6 months) with a physical exam and x-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

 to evaluate the magnitude of the curve.

Genetic testing allows physicians to identify individual patients' risk of curve progression with a surrogate outcome, meaning risk of progression can be known without patients being subjected to frequent office visits and exposure to radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

 from multiple radiographs.

Adolescent Idiopathic Scoliosis is a polygenic trait, meaning it is affected by the characteristics of more than a single gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. The heritability of scoliosis has long been suspected, and many research projects have been conducted in search of the genes responsible for the disease.

First Genetic Test for AIS

The first genetic test for AIS was developed between 2003 and 2008 by Axial Biotech, Inc. in Salt Lake City, Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

. The test is called the ScoliScore
ScoliScore
The ScoliScore AIS Prognostic Test is a genetic test, which analyzes the DNA of patients who are diagnosed with Adolescent Idiopathic Scoliosis, the most common type of scoliosis. The test shows the likelihood of spinal curve progression...

 AIS Prognostic Test. It was made commercially available in September, 2009 and is distributed by DePuy Spine, Inc.. Axial Biotech performed a genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

-wide association study, testing millions of genetic markers to find any associated with scoliosis
Scoliosis
Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C" than a straight line...

. The study of DNA heritability was enhanced through the use of rich genealogical data available in Utah. Utah contains the headquarters of The Church of Jesus Christ of Latter-day Saints, which emphasizes the knowledge of ancestry and genealogy. Over the course of the research, DNA samples from over 9500 patients from 100 clinical sites worldwide were analyzed.

Researchers at Axial Biotech identified 53 genetic markers (28 which, when positive, contribute to the progression of the scoliosis curve and 25 which, when positive, protect against the progression of the curve.) The ScoliScore test was developed around these 53 markers.

The ScoliScore AIS Prognostic Test has been shown to be effective in detecting the genotypes for 53 genetic markers found in clinical trials to be associated with curve progression in self-reported Caucasian (North American, South American, European, Eastern European, Middle Eastern descent) male/female patients from 9 through 13 years of age, who have been diagnosed with Mild AIS (10-25 degree Cobb Angle).

External links

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