narrow spaces between the vertebrae (narrow intervertebral spaces)

congenital spinal stenosis (a narrowing of the space around the spinal cord)

delayed bone development (for example, the fontanelle, or "soft spot" on the baby's head will take longer than normal to close - often as late as two years of age)

brittle bones

pigeon chest or tunnel chest (pectus carinatum or pectus excavatum) - pectus deformity affects 80% of individuals.

excessive backward and/or side-to-side curvature of the spine (kyphosis and/or scoliosis) (80% of individuals are affected).

	at least 47% of affected males have progressive kyphoscoliosis (32% of females) [Hunter 2002]
	respiratory compromise can happen due to this.

short stature - 5th percentile for height (Affects 95% of individuals - Average height in reported adult males is approximately 143 cm - the shortening of stature is often exacerbated by a severe kyphoscoliosis. Females are less severely affected with approximately 50% lying above the 10th percentile.)