Rationale: Despite several decades of research, the exact etiology of adolescent idiopathic scoliosis (AIS) remains unclear. In AIS, spine curvature begins with and progresses during the adolescent growth spurt. Previous studies are only performed on populations with already established scoliosis and normal spinal growth (of bone and IVD tissue) during adolescence has also not been defined. Growth pattern differences may exist between scoliotic and nonscoliotic subjects. Previous studies support the hypothesis that AIS is a spinal deformity that starts with decompensation in the IVD and is linked to sagittal spinal alignment. However, to understand its cause and pathogenic mechanism, the changes to the adolescent spine must be assessed longitudinally during the growth period coinciding with the period prior to and during the onset of AIS. Ideally this should include a cohort who do and do not develop AIS and their assessment must be minimally harmful, without radiation exposure. Certain populations are at increased risk for scoliosis development (i.e. girls with family members with scoliosis and 22q11.2DS patients). New imaging modalities (boneMRI, 3D spinal ultrasound) allow for non-radiographic monitoring of spinal growth.

Objective: The primary objectives is: To longitudinally evaluate the substantial differences in anatomical changes in the spine during adolescent growth in girls, at increased risk for scoliosis development, and in adolescent 22q11.2DS patients, that do and do not develop AIS.

The secondary objectives are:

• To develop spine specific (IVD/endplates) maturity assessment grading.
• To implement radiation-free imaging methods for spinal monitoring in adolescent patients at risk for scoliosis development.
• To create a longitudinal dataset for patient specific spinal biomechanical assessment.

Study design: Prospective observational cohort study

Study population: 60 adolescent girls (8-10 years old) at increased risk for idiopathic scoliosis development (an older sibling or parent diagnosed with idiopathic scoliosis) (Cohort-1) and 60 adolescent girls and boys with 22q11.2DS with increased risk for idiopathic-like scoliosis development (Cohort-2).

Intervention: none

Main study parameters/endpoints: Spinal MR imaging of the thoracic and lumbar spine will be performed at 5 time points between 8 or 9 and 15 or 16 for girls and boys respectively to evaluate possible changes in the 3D anatomy of the spine. The main study parameter will be the longitudinal changes in segmental axial rotation on boneMRI of the thoracolumbar spine in subjects that do and do not develop AIS.

Secondary endpoints: Changes in bone and intervertebral disc morphology, lateral shift of the nucleus pulposus. These will be correlated to assessments of growth, skeletal maturity and spinal alignment.

Inclusion Criteria:

Cohort 1:

• Female,
• 8, 9 or 10 years old
• An older sibling, twin or parent diagnosed with AIS

Cohort 2:

• Diagnosed with 22q11.2DS
• Girls: 8, 9 or 10 years old.
• Boys: 9, 10 or 11 years old.

All

• No clinical signs of scoliosis at inclusion (physical examination by forward bending test and Bunnell Scoliometer assessment with a cut-off value of 7°.
• Written informed consent of parents/legal representatives.

Exclusion Criteria:

• Contraindications for MR imaging
• Early-onset scoliosis or other spinal deformities
• Other syndromes or neuromuscular disease associated with scoliosis
• Clinical signs of >1cm leg length discrepancy
• Other diseases or injuries, that are related to abnormal spinal growth, posture, activity levels, or scoliosis development.

Cohort 1: 60 adolescent girls (8-10 years old) at increased risk for idiopathic scoliosis development (an older sibling or parent diagnosed with idiopathic scoliosis) Cohort 2: 60 adolescent girls or boys with the 22q11.2DS with increased risk for idiopathic-like scoliosis development.