Early-onset FSHD (Infantile FSHD)

Up to 10% of FSHD cases are classified as ‘early-onset’ or ‘infantile’ FSHD, with facial weakness appearing before the age of five, or arm/shoulder weakness appearing before the age of 10. This rare form of FSHD has an estimated prevalence of 1 in 200,000 people.

In contrast with people with ‘classical’ or adult-onset FSHD, whose main symptoms start to appear in adolescence and adulthood, children with early-onset FSHD generally experience more rapid disease progression and more severe symptoms.

Classical FSHD typically progresses slowly, with around 20-25% of those over age 50 needing a wheelchair. In contrast, people with early-onset FSHD may need a mobility device sooner, by their 20s or 30s, and a few require a wheelchair in their first decade. Children with early-onset FSHD also face a higher risk of complications involving vision and hearing, though these are treatable if caught early.

Early-onset FSHD is not as well understood as classical FSHD, and so more research is needed. At the moment, we don’t know why early-onset FSHD is more severe than adult-onset disease. It appears that many children with FSHD have much fewer D4Z4 repeats, which is linked to more severe symptoms in adults. Research also suggests that there may be other factors, including multiple mutations working in synergy, that make the symptoms and progression more severe.

FSHD Global Research Foundation commissioned a research grant in memory of our Patron, Monica Ellis, dedicated studying early-onset FSHD.