SMN1 and scoliosis: Only BMI/age z-score at baseline and gender were significantly contributing (p < 0.002 and < 0.001) to the changes (Table 1), with no significant impact of SMN2 copy number, SMA function, non-invasive ventilation, nutritional status, and scoliosis surgery on rate of progression (p for interaction between time and other variables > 0.05).