What is the prevalence of Lennox-Gastaut syndrome (LGS)?

Updated: Nov 09, 2018
  • Author: Koshi A Cherian, MD; Chief Editor: Amy Kao, MD  more...
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Overall, LGS accounts for 1-4% of patients with childhood epilepsy but 10% of patients with onset of epilepsy when younger than 5 years. The prevalence of LGS in Atlanta, Georgia, was reported as 0.26 per 1000 live births.

LGS is more common in boys than in girls. The prevalence is 0.1 per 1000 population for boys, versus 0.02 per 1000 population for girls (relative risk, 5.31).

The mean age at epilepsy onset is 26-28 months (range, 1 d to 14 y). The peak age at epilepsy onset is older in patients with LGS of an identifiable etiology than in those whose LGS has no identifiable etiology. The difference in age of onset between the group of patients with LGS and a history of West syndrome (infantile spasm) and those with LGS without West syndrome is not significant. The average age at diagnosis of LGS in Japan was 6 years (range, 2-15 y).

Epidemiologic studies in industrialized countries (eg, Israel, Spain, Estonia, Italy, Finland) have demonstrated that the proportion of epileptic patients with LGS seems relatively consistent across the populations studied and similar to that in the United States. The prevalence of LGS is 0.1-0.28 per 1000 population in Europe. The annual incidence of LGS in childhood is approximately 2 per 100,000 children. [5]

Among children with intellectual disability, 7% have LGS, while 16.3% of institutionalized patients with intellectual disability have LGS.

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