The long-term outlook (prognosis) for people with Klippel-Feil Syndrome varies depending on the specific features and severity in each affected person.
In general, people with minimal involvement can lead normal, active lives and may have no significant restrictions or symptoms. People with additional abnormalities and/or severe forms of the condition may require careful and routine follow-up, but can have a good prognosis if symptoms and complications are treated early.
Complications associated with Klippel-Feil Syndrome do not normally develop before the age of 25 years and some may be treated surgically.
But because Klippel-Feil Syndrome is progressive and depending upon the severity of other conditions associated with it, it's been found that the life expectancy can be between 30 - 45 years old, in some cases, not all.