Skeletal abnormalities may include abnormal front-to-back and side-to-side curvature of the spine (kyphoscoliosis) and unusual prominence of the breastbone (sternum) (pectus carinatum).

Kyphoscoliosis is one of the causes of restrictive lung disease. It can lead to chronic (hypercapnic respiratory failure and hypoxemia.

Scoliosis and kyphosis/kyphoscoliosis are not a diagnosis in themselves. Such deformities are mostly a symptom complex correlated to dozens of types of syndromic associations. The rate curve progression and the final severity of congenital spine tilting are related to 3 factors: (a) the type of vertebral malformation present, (b) the patient’s phenotype, and (c) the diagnosis. 

It has been suggested that nocturnal nasal ventilation can significantly improve nocturnal and daytime blood gases, pulmonary function, and symptoms of hypoventilation for patients with severe kyphoscoliosis.