Adolescent idiopathic scoliosis (Kou, 2019) – Is scoliosis genetic?

Scoliosis is a sideways curvature of the spine.

Nebula Genomics DNA Report for Scoliosis

Is scoliosis genetic? We created a DNA report based on a study that attempted to answer this question. Below you can see a SAMPLE DNA report. To get your personalized DNA report, purchase our Whole Genome Sequencing!

Sample report of scoliosis from Nebula Genomics
Sample variants associated with scoliosis
To learn more about how Nebula Genomics reports genetic variants in the table above, check out the Nebula Research Library Tutorial.

Introduction (Part 1 of Is scoliosis genetic?)

Scoliosis causes an abnormal S-shaped or C-shaped curve in the spine. It can happen on either side of the spine and in different areas. Specifically, it is a lateral deviation of the spine from the longitudinal axis with rotation (twisting) of the vertebrae around the longitudinal axis and rotation of the vertebral bodies. Overall, this leads to structural spinal deformities.  

An animation of scoliosis
3D Medical Animation still shot of spine having scoliosis. Wikipedia. CC-Attribution-Share Alike 4.0 International

The onset of the condition normally occurs in the late childhood or early teens (children ages 10-15 years old), during the growth spurt shortly before puberty. Most cases are considered mild scoliosis, but others may get worse as children continue to grow. Some cases of scoliosis even become debilitating. The worst cases affect the amount of space in the chest, negatively affecting the function of the lungs. 

With treatment and monitoring, most children with the condition go on to lead healthy, active lives. 

Classification

The condition is classified according to the cause and time of origin, the location and pattern of the curvatures, the extent (angles of curvature and degrees of rotation), and the orientation of the curvatures (left, right). When the cause is unknown, it is called idiopathic scoliosis and this is the most common type of scoliosis. About 90% of all cases are this type. In a small percentage of cases (10%), when the cause is known, it is a symptomatic or secondary scoliosis.

Some types include:

  • Congenital scoliosis: occurs when the spine does not develop fully in the womb
  • Early onset scoliosis: occurs before puberty (between birth and age 10)
  • Adolescent idiopathic scoliosis: occurs when a child is growing. Spine curvatures and twisting occur at the same time
  • Degenerative scoliosis: occurs in older adults as bones age. This type usually occurs in the lumbar spine (lower spine)
  • Neuromuscular scoliosis: a curvature of the spine caused by a neurological or muscular condition such as cerebral palsy, muscular dystrophy, or spina bifida
  • Scheuermann’s kyphosis: occurs when the front sections of the vertebrae (small bones that make up the spine) grow more slowly than the back sections during childhood
  • Syndromic scoliosis: spine curves as the result of a separate condition

Is scoliosis hereditary?

Researchers suspect that several genes may contribute to patients having a genetic predisposition to the condition. Even more contribute to how severe the disorder is and whether the spinal curve progresses. Although many genetic mutations have been mildly associated with the condition, very few have been clearly linked. 

According to ScolioSMART, nearly a third of patients with adolescent idiopathic scoliosis have a family history of the condition, and first-degree relatives of patients have an 11 percent chance of developing it themselves. Additionally, genetic studies found scoliosis patients with 14 or more of 28 genomic variants were 33% more likely to develop a severe form of the disorder.

Epidemiology (Part 3 of Is scoliosis genetic?)

Scoliosis is a fairly common disease. In 2013, literature review suggested there was anywhere from 0.47-5.2% prevalence of adolescent idiopathic scoliosis worldwide. Most sources average this out to be around 3%, especially in the United States. 

Generally, the condition is more common in females than males. Additionally, you have a greater chance of developing the adolescent idiopathic form if you have a family member with this condition. 

Symptoms (Part 4 of Is scoliosis genetic?)

Symptoms vary depending on the severity of the disorder. Common visible signs and symptoms may include:

  • Uneven shoulders
  • One shoulder blade that appears more prominent than the other
  • Uneven waist
  • One hip higher than the other
  • Trouble breathing (more severe cases)
  • Chest pain (rare)

If a scoliosis curve gets worse, the spine will also rotate or twist, in addition to curving side to side. This can be observed as ribs on one side of the body will stick out farther than on the other side.

An x-ray of a curved spine
X-ray image of a 15-year old with scoliosis. Wikipedia. CC-Attribution-Share Alike 3.0 Unported.

In the most severe cases, the rib cage may press against the heart and lungs, making it difficult to breath and leading to heart disease. Young people who develop scoliosis are also at a higher risk of developing chronic back problems. 

If the condition worsens so that physical signs are noticeable, it often negatively impacts self-esteem and mental wellbeing. 

Causes (Part 5 of Is scoliosis genetic?)

In a majority of cases (about 90%), the cause of scoliosis is unknown. It is observed that the condition runs in families, suggesting a hereditary component. Females are also more likely to develop the condition than males. Onset is most likely to occur around the time of puberty, when children tend to grow rapidly. Overall, it may be the result of genetic and environmental factors, although this is more likely true in later onset forms of scoliosis.

There are some conditions that are identified as risk factors for scoliosis including:

  • Neuromuscular medical conditions such as cerebral palsy, a group of nervous system disorders that affect movement, learning, hearing, seeing, and thinking and muscular dystrophy, a group of genetic disorders that result in muscle weakness
  • Birth defects that affect the spinal bones, such as spina bifida
  • Spinal injuries or infections

Diagnosis (Part 6 of Is scoliosis genetic?)

A physical exam is usually the first step to diagnose scoliosis, especially in young children. The doctor will observe a child standing straight, with arms at their sides. They can check for spine curvature and whether shoulders and hips are symmetrical. They may then ask the child to stand and bend forward at the waist with arms hanging down. This test, sometimes called the Adam’s test, allows the doctor to determine if one side of the rib cage is more prominent than the other or if there is additional curvature in the upper and lower back.

An x-ray of the spine is normally the next step in the diagnosis procedure. These images of the spine will confirm the diagnosis and reveal the severity of the spinal curvature. 

Diagnosing scoliosis
The position test and x-rays used to confirm scoliosis. Wikipedia. CC-Attribution 2.0 Generic.

Other imaging tests are less common, but may be recommended if another condition is also suspected. These additional tests may include MRIs, CT scans, and bone scans. 

Treatment (Part 7 of Is scoliosis genetic?)

Scoliosis treatment options are very dependent on the individual and the progression of the disorder. Most children develop only a mild case of the condition which does not require major treatment. If observed during puberty, children are normally monitored regularly to determine if the condition worsens over time. Doctors take a number of factors into consideration when deciding on a more drastic treatment such as a brace or scoliosis surgery:

  • Sex
  • Severity of the curve
  • Curve patterns (S curves tend to be more severe than C curves)
  • Location of the curve (centered curves tend to worsen more often)
  • Stage of bone growth (the condition does not usually progress in bones that have stopped growing)

Braces

Braces are the most recommended type of medical advice for children who are still growing and who exhibit moderate scoliosis. Although a brace cannot fix damage that has already occurred, it will stop the curve from getting worse. This is why braces are most effective in cases that are diagnosed early. 

The most common type of brace is made of plastic and can fit easily under normal clothing. Most children are able to maintain their daily physical activities while wearing the brace. It’s effectiveness is directly related to how often it is worn and why it is normally worn day and night. Once children stop growing, a brace will no longer be effective so it’s use is discontinued. 

The American Association of Neurological Surgeons recommends braces for children still growing who have a curvature more than 25 to 40 degrees.

Surgery

Severe forms of the condition that worsen with time may require a special type of surgery called a spinal fusion. Surgery is usually reserved for patients who have a curvature of over 40 degrees. 

This type of surgery fuses two vertebrae together so that they cannot move independently. Bone grafts made of pieces of bone or a bone-like material are placed between the vertebrae. Finally, metal rods, hooks, screws or wires typically hold the spine straight while the old and new bone fuses together. 

If the child is still growing, an adjustable rod that can be lengthened as the child grows may be installed. All surgeries come with some risk of complications, including bleeding, infection, and nerve damage. 

Prognosis (Part 8 of Is scoliosis genetic?)

The condition affects people differently. In mild to moderate cases, most people with scoliosis live full lives with few to no physical limitations. In more severe instances, people might find discomfort, pain, or mental distress. 

Coping can be especially difficult for children and teens. Strong peer relationships and support groups may help children who are having difficulty in managing. Support groups specifically for families affected by scoliosis may be especially useful in providing advice, resources, and connections with others who face similar challenges. 

For more information on this condition in children and teens, you could reference the latest research from the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

If you liked this article, you should check out our other posts in the Nebula Research Library!