Autosomal dominant inheritance of centrotemporal sharp waves in rolandic epilepsy families.
OBJECTIVE
Centrotemporal sharp (CTS) waves, the electroencephalogram (EEG) hallmark of rolandic epilepsy, are found in approximately 4% of the childhood population. The inheritance of CTS is presumed autosomal dominant but this is controversial. Previous studies have varied considerably in methodology, especially in the control of bias and confounding. We aimed to test the hypothesis of autosomal dominant inheritance of CTS in a well-designed family segregation analysis study.


METHODS
Probands with rolandic epilepsy were collected through unambiguous single ascertainment. Siblings in the age range 4-16 years underwent sleep-deprived EEG; observations from those who remained awake were omitted. CTS were rated as present or absent by two independent observers blinded to the study hypothesis and subject identities. We computed the segregation ratio of CTS, corrected for ascertainment. We tested the segregation ratio estimate for consistency with dominant and recessive modes of inheritance, and compared the observed sex ratio of those affected with CTS for consistency with sex linkage.


RESULTS
Thirty siblings from 23 families underwent EEG examination. Twenty-three showed evidence of sleep in their EEG recordings. Eleven of 23 recordings demonstrated CTS, yielding a corrected segregation ratio of 0.48 (95% CI: 0.27-0.69). The male to female ratio of CTS affectedness was approximately equal.


CONCLUSIONS
The segregation ratio of CTS in rolandic epilepsy families is consistent with a highly penetrant autosomal dominant inheritance, with equal sex ratio. Autosomal recessive and X-linked inheritance are rejected. The CTS locus might act in combination with one or more loci to produce the phenotype of rolandic epilepsy.
Bali
Bhavna
B
Department of Epidemiology, Columbia University, New York, New York 10032, USA.
Kull
Lewis L
LL
Strug
Lisa J
LJ
Clarke
Tara
T
Murphy
Peregrine L
PL
Akman
Cigdem I
CI
Greenberg
David A
DA
Pal
Deb K
DK
D000293:Adolescent; D002540:Cerebral Cortex / Q000503:physiopathology; D002648:Child; D002874:Chromosome Mapping; D004569:Electroencephalography / Q000706:statistics & numerical data*; D019305:Epilepsy, Rolandic / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D005190:Family; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D005799:Genes, Dominant / Q000235:genetics / Q000502:physiology; D005808:Genes, Recessive / Q000235:genetics / Q000502:physiology; D008040:Genetic Linkage / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000145:classification / Q000208:ethnology / Q000235:genetics*; D006801:Humans; D008297:Male; D017678:Sex Distribution; D035781:Siblings; D012892:Sleep Deprivation; D012894:Sleep Stages / Q000502:physiology