<<Disclaimer: Verify this information before applying it to your situation.>>

There are many causes, and a couple of variants of kyphosis. However,
abnormalities in bone mineralization are very common in celiac disease, and
such abnormalities are sometimes the cause of such spinal deformations.

When a parent sees this condition in a first degree relative, knowing
themselves to be intolerant to gluten (regardless of testing) it seems very
reasonable to have his son tested for celiac disease.

best wishes,
Ron Hoggan