Visible deformities can be seen in some children. Often that's when the diagnosis is made. In many cases, the condition is present but remains hidden. Any of the bones can be affected but deformities of the upper arm, forearm, knee, tibia (lower leg), and ankle are the most obvious.

There is a wide range of severity for this disease. Gender doesn't seem to be linked with how mild or severe the condition is. Even within one family, there can be an inconsistent pattern. Hereditary exostosis is autosomal dominant. This means each of your husband's children will have a 50 per cent chance of inheriting the disorder.

Because males and females are equally affected, all of his children who have this disorder will be likely to have affected children. Sometimes an autosomal dominant disorder skips generations but hereditary exostosis has a 96 per cent penetrance, meaning it affects nearly all generations.

Generally, when a person with this condition reaches maturity, and their bones stop growing, the exostoses also stop growing. In a small number of patients, the tumors can become cancerous. Regular screening is advised for anyone with this condition.