Evaluating the frequency and characteristics of seizures in 142 Japanese patients with Prader-Willi syndrome.

Prader-Willi syndrome (PWS) has not been widely regarded as a disorder with a risk factor for seizures. We retrospectively investigated the frequency and characteristics of seizures and examined genotype-phenotype correlations with respect to seizures in PWS. We analyzed 142 patients with PWS and identified 31 (22%) with seizures. The most common seizure type was febrile convulsion (12%, 17/142). Epilepsy occurred in 6% of the patients in our cohort (9/142). The frequencies of febrile seizure and epilepsy in PWS were higher than those in the general population. Our study suggested that the frequency of seizures was not associated with genotypes of PWS (P = 0.35). In our study patients with PWS, 68% of the patients with seizures experienced initial episodes before they were 2 years old, and the seizures were relatively easier to manage.