Disease expression among probands with juvenile myoclonic epilepsy and their family members in two population groups

We report clinical and EEG features of 65 probands with juvenile myoclonic epilepsy (JME) and the occurrence and character of epilepsy among 664 blood relatives of 26 of the 65 probands with a positive family history of seizures. Forty-six families from India and 19 families from the United States were investigated. Among the probands, sex distribution was equal; the mean age at onset of generalized tonic-clonic seizures (GTCS) and myoclonic jerks was 14.2 and 14.3 years, respectively; myoclonic jerks alone occurred in 2 (3%); 5 (8%) had absence seizures; and bilaterally symmetrical polyspike and wave complexes were evident during interictal EEG in 50 (77%). Twenty-six probands (40%) had blood relatives with seizures. Clinical and EEG features were similar in Indian and American probands and in probands with and without a family history of seizures. Sixty-two blood relatives had seizures: 38 (61%) had idiopathic generalized epilepsy (IGE), including 11 (18%) with JME; 9 (15%) had single, spontaneous generalized seizures before age 30 years; and the remainder had febrile convulsions (4, 6%) or symptomatic, partial or unclassified epilepsy (11, 18%). Both the proportion of family members observed to have epilepsy and the epilepsy syndrome expressed in family members varied as a function of the degree of relation. First-degree relatives had greater occurrence of epilepsy, IGE and JME than did more distant blood relatives. These data suggest that JME is a complex genetic disorder and support a multigenic pattern of inheritance.

Duke Scholars

Author Rodney Allan Radtke Neurology, Epilepsy and Sleep

Author James O'Connell McNamara Sr. Neurobiology