Advertisement

Relationship between severity of epilepsy and developmental outcome in Angelman syndrome

      Abstract

      To clarify the relationship between the degree of developmental disturbance and the severity of epilepsy in Angelman syndrome, we investigated 11 patients and measured both clinical outcomes and EEG parameters. Seven patients were followed up until after 8 years of age. Eight patients were found to have 15q11–q13 deletions.
      All patients experienced epileptic seizures and all but one displayed nonconvulsive status epilepticus (NCSE) during the period of observation. Epileptic seizures, including NCSE, disappeared by around 8 years of age. In addition, specific epileptic discharges, as measured by EEG, tended to subside with age. Although development seemed almost normal or only slightly delayed during the first 6 months of life, all patients eventually developed severe retardation. Two patients displayed very severe retardation and were unable to comprehend language or walk independently at the last follow-up. Only one patient was able to speak a few meaningful words. In one of the most severely affected patients, who showed the earliest onset of seizures and NCSE, it is possible that the repetitive bouts of NCSE might be responsible for the severe developmental outcome. However, the other patient with particularly severe retardation did not experience NCSE, while the patient with the most favorable outcome had repetitive episodes of NCSE.
      Therefore, we conclude that the severity of developmental disturbance in Angelman syndrome is not necessarily related to the degree of epilepsy. However, intensive therapy for NCSE might still be justified because there are some patients in whom NCSE results in a transient and sometimes permanent decline in mental and motor functioning.

      Keywords

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Brain and Development
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Philippart M.
        Rett and Angelman's syndromes: models of arrested development.
        Pediatr Neurol. 2001; 25: 288-294
        • Zori R.T.
        • Hendrickson J.
        • Woolven S.
        • Whidden E.M.
        • Gray B.
        • Williams C.A.
        Angelman syndrome: clinical profile.
        J Child Neurol. 1992; 7: 270-280
        • Hoffmann-Riem M.
        • Diener W.
        • Benninger C.
        • Rating D.
        • Unnebrink K.
        • Stephani U.
        • et al.
        Nonconvulsive status epilepticus—a possible cause of mental retardation in patients with Lennox-Gastaut syndrome.
        Neuropediatrics. 2000; 31: 169-174
        • Boyd A.
        • Harden A.
        • Patton M.A.
        The EEG in early diagnosis of the Angelman (happy puppet) syndrome.
        Eur J Pediatr. 1988; 147: 508-513
        • Laan L.A.E.M.
        • Renier W.O.
        • Arts W.F.M.
        • Buntinx I.M.
        • V.d. Burget IJAM
        • Stroink H.
        • et al.
        Evolution of epilepsy and EEG findings in Angelman syndrome.
        Epilepsia. 1997; 38: 195-199
        • Jolleff N.
        • Ryan M.M.
        Communication development in Angelman's syndrome.
        Arch Dis Child. 1993; 69: 148-150
        • Penner K.A.
        • Johnston J.
        • Faircloth B.H.
        • Irish P.
        • Williams C.A.
        Communication, cognition, and social interaction in the Angelman syndrome.
        Am J Med Genet. 1993; 46: 34-39
        • Clayton-Smith J.
        Angelman syndrome: evolution of the phenotype in adolescents and adults.
        Dev Med Child Neurol. 2001; 43: 476-480
        • Robb S.A.
        • Pohl K.R.E.
        • Baraitser M.
        • Wilson J.
        • Brett E.M.
        The ‘happy puppet’ syndrome of Angelman: review of the clinical features.
        Arch Dis Child. 1989; 64: 83-86
        • Angelman H.
        ‘Puppet’ children: a report on three cases.
        Dev Med Child Neurol. 1965; 7: 681-688
        • Viani F.
        • Romeo A.
        • Viri M.
        • Mastrangelo M.
        • Lalatta F.
        • Selicorni A.
        • et al.
        Seizure and EEG patterns in Angelman's syndrome.
        J Child Neurol. 1995; 10: 467-471
        • Guerrini R.
        • DeLorey T.M.
        • Bonanni P.
        • Moncla A.
        • Dravet C.
        • Suisse G.
        • et al.
        Cortical myoclonus in Angelman syndrome.
        Ann Neurol. 1996; 40: 39-48
        • Sugimoto T.
        • Yasuhara A.
        • Ohta T.
        • Nishida N.
        • Saitoh S.
        • Hamabe J.
        • et al.
        Angelman syndrome in three siblings: characteristic epileptic seizures and EEG abnormalities.
        Epilepsia. 1992; 33: 1078-1082
        • Matsumoto A.
        • Kumagai T.
        • Miura K.
        • Miyazaki S.
        • Hayakawa C.
        • Yamanaka T.
        Epilepsy in Angelman syndrome associated with chromosome 15q deletion.
        Epilepsia. 1992; 33: 1083-1090
        • Elia M.
        • Guerrini R.
        • Musumeci S.A.
        • Bonanni P.
        • Gambardella A.
        • Aguglia U.
        Myoclonic absence-like seizures and chromosome abnormality syndromes.
        Epilepsia. 1998; 39: 660-663
        • Minassian B.A.
        • DeLorey T.M.
        • Olson R.W.
        • Philippart M.
        • Bronstein Y.
        • Zhang Q.
        • et al.
        Angelman syndrome; correlations between epilepsy phenotypes and genotypes.
        Ann Neurol. 1998; 43: 485-493