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Causes of epilepsies: Insights from discordant monozygous twins
Author(s) -
Briellmann Regula S.,
Jackson Graeme D.,
TornBroers Yvonne,
Berkovic Samuel F.
Publication year - 2001
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/1531-8249(200101)49:1<45::aid-ana9>3.0.co;2-f
Subject(s) - epilepsy , monozygotic twin , medicine , etiology , magnetic resonance imaging , atrophy , twin study , pathology , radiology , heritability , psychiatry , genetics , biology
Whereas some patients with epilepsy have known acquired or genetic causes, in many the cause is unknown. By analyzing monozygotic twins, discordant for epilepsy, subtle etiological factors may be detected. We analyzed 12 monozygotic, discordant twins for factors explaining discordancy. These factors were presence of major clinical risk factors, presence of possibly epileptogenic lesions on brain magnetic resonance imaging (MRI), and quantitative brain volume abnormalities. Major risk factors, with associated acquired lesions were found in 4 of 12 twins. An MRI lesion without a major risk factor was found in a further 4 of 12 twins. Two of these had unilateral malformations of cortical development, 1 had bilateral periventricular heterotopia, and 1 had focal atrophy. Significant twin–twin differences in MRI volumes without obvious MRI lesions or major risk factors were found in 2 of 12 twins. Both had larger volumes than their co‐twins, and idiopathic generalized epilepsy. No clinical or MRI findings accounting for discordance for epilepsy were found in 2 of 12 twins. In 10 of 12 pairs a clinical or MR correlate of epilepsy was found; some of those were subtle and only apparent by twin–twin comparison. They may be due to occult acquired factors, such as prenatal insults, or to genetic abnormalities resulting from postfertilization genetic processes. Ann Neurol 2001;49:45–52