Gene associated with adolescent idiopathic scoliosis identified

Researchers from the RIKEN Center for Integrative Medical Sciences in Japan have identified the first gene to be associated with adolescent idiopathic scoliosis (also called AIS) across Asian and Caucasian populations. The gene is involved in the growth and development of the spine during childhood.

Their study is published today in the journal Nature Genetics.

AIS is the most common pediatric skeletal disease, affecting approximately 2% of school-age children. The causes of scoliosis remain largely unknown and brace treatment and surgery are the only treatment options. However, many clinical and genetic studies suggest a contribution of genetic factors.

To understand the causes and development of scoliosis, Dr Ikuyo Kou, Dr Shiro Ikegawa and their team have tried to identify genes that are associated with a susceptibility to develop the condition.

By studying the genome of 1,819 Japanese individuals suffering from scoliosis and comparing it to 25,939 Japanese individuals, the team identified a gene associated with a susceptibility to develop scoliosis on chromosome 6. The association was replicated in Han Chinese and Caucasian populations.

The researchers show that the susceptibility gene, GPR126, is highly expressed in cartilage and that suppression of this gene leads to delayed growth and bone tissue formation in the developing spine. GPR126 is also known to play a role in human height and trunk length.

Scoliosis is a condition in which the spine- in addition to the normal front to back curvature- has an abnormal side- to- side "S- " or "C"- shaped curvature. The spine is also rotated or twisted, pulling the ribs along with it to form a multidimensional curve.

The Scoliosis Research Society defines scoliosis as a curvature of the spine measuring 10 degrees or greater on x- ray. The condition isn't rare. It mainly affects girls- many of whom have mild forms of scoliosis, are never even aware of it, and never need treatment.

Three to five children out of every 1,000 develop spinal curves that are considered large enough to require treatment. Idiopathic scoliosis does tend to run in families, although no one genetic link has been confirmed.

Scoliosis occurs, and is treated, as three main types:

idiopathic scoliosis: the most common form, with no definite cause, mainly affecting adolescent girls, but existing in three age groups:
adolescent idiopathic scoliosis
juvenile idiopathic scoliosis
infantile (early- onset) idiopathic scoliosis

neuromuscular scoliosis: associated with a neuromuscular condition such as cerebral palsy, myopathy or spina bifida