Who develops LGS?
The prevalence of LGS or how many people have LGS at any point in time is about 0.26 per 1000. This means that 26 out of 100,000 people are living with LGS yearly. When only childhood epilepsies are considered, 1 out of 10 children with seizures beginning in the first 5 years of their life have LGS. It is more common in boys than girls.
Seizures usually begin in children at 26 to 28 months old with the majority starting before 7 years old.
Children who have other developmental or intellectual problems have a greater chance of being diagnosed with LGS.
Up to 17% of adults with cognitive problems who live in supported facilities and are unable to live independently have LGS.
The diagnosis of LGS can be difficult to make since it may take many years for different symptoms to develop. It is hard to know for sure how many people are affected at different ages.
No racial differences have been documented.