Nearly all children with SIOD are short-statured, the first obvious sign. Short-stature is caused by a skeletal disorder called spondyloepiphyseal dysplasia, where the bones in the spine, arms and legs do not fully develop. A doctor might also notice that your child is failing to grow properly or has immune system problems (i.e. a T-cell deficiency leading to a weak immune system that leaves your child vulnerable to serious infections). Fatigue and kidney disease are also common signs of SIOD.