We have identified a region with characteristics of a paternal-specific methylation imprint at the human H19 locus. This region, extending from -2.0 kb upstream to the start of transcription, is heavily methylated in sperm and on the paternal allele in somatic cells. This methylation was preserved during pre-implantation. Structural analysis revealed the presence of CpG islands and a large direct repeat with a 400 bp sequence reiterated several times, but no significant sequence homology to the corresponding region of the mouse H19 gene. These findings could suggest a role for secondary DNA structure in genomic imprinting across the species, and they also present a puzzling aspect of the evolution of the H19 regulatory region in human and mouse.

Three children with Leber's congenital amaurosis, agenesis of the cerebellar vermis, and infantile polycystic kidneys are described. The common clinical findings of three unrelated patients (two boys and one girl) included severe visual impairment from early infancy, profound psychomotor retardation, hypotonia, nystagmus, characteristic facial appearance with blepharoptosis, and progressive chronic renal insufficiency. The two boys died of uremia at ages 13 and 12 years. The common pathological findings in these two patients consisted of minor disproportions of cerebral lobes, almost total aplasia of the cerebellar vermis, micropolygyria of the dentate nuclei, malformations of the brain stem (including pachygyria of the inferior olivary nuclei and partial absence and anomalous position of the pyramidal tracts), and infantile polycystic kidneys; there was fatty liver in one case and hepatic fibrosis in the other. The clinicopathological findings of our two patients were entirely compatible with those of patients previously reported by Arima and other Japanese authors. Therefore, these patients seem to comprise a distinct clinicopathological entity, cerebro-oculo-hepato-renal syndrome (Arima's syndrome), different from other syndromes with retinal, cerebellar, and renal abnormalities.

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Summary: Purpose: To clarify the relation between quantitative electroencephalogram (EEG) findings and outcome following corpus callosotomy (CC).Methods: The degree of bilateral synchrony and morphologic similarity of spike-wave discharges was analyzed by using a cross-correlation analysis and the measurements of amplitude differences between bilateral homologous regions in 22 patients who underwent anterior CCs for intractable symptomatic generalized epilepsies (SGE; 17 patients) and frontal lobe epilepsy (five patients).Results: Interictal generalized synchronous spike-wave (GSSW) bursts in the SGE patients were disrupted and changed to unilateral spike-waves (USWs) in 11 patients and to bilaterally independent spike-waves (BISWs) in six. The USW group had better surgical outcome than the BISW group. Preoperatively, the USW group had significantly lower interhemispheric synchrony (IS) and fewer regional changes in the side leading in time and the side dominant for amplitude, suggesting unilaterally predominant epileptogenesis that triggered the secondary bilateral synchrony. Postoperatively, the BISW group had a more marked reduction in IS because of independent discharges from bilateral epileptogenic areas, and the USW group had a greater amplitude difference because of unilateralized spike-waves. In addition, an excellent surgical outcome was related to (a) the preoperative degree of the morphologic similarity of the bilateral spike-waves (only a small variation during a burst of spike-waves) and the few instances of regional changes in the side leading in time and in the side dominant for amplitude; and (b) to large postoperative amplitude differences.Conclusion: Preoperative quantitative EEG analyses enabled us to predict the underlying conditions of epileptogenesis and the surgical outcomes in patients undergoing CC. Key Words: Corpus callosotomy-Epilepsy-Cross-correlation analysis-EEG-Surgical outcome.Because the corpus callosum is thought to be a major pathway in the bilateral generalization of seizure discharges, corpus callosotomies (CCs) have been performed to reduce the frequency and severity of intractable seizures, especially secondarily generalized seizures, and they have provided a marked improvement in seizure control for many patients (1-1 1). Electroencephalogram (EEG) changes reported after CCs consist of a disruption of bilateral synchrony associated with amplitude asymmetry, localization or lateralization of seizure discharges, and the appearance of bilaterally independent spike-waves (BISWs) (3,(12)(13)(14)(15). However, the relation Accepted February 25, 1999.Address correspondence and reprint requests to Dr. T. Matsuzaka at Department of Pediatrics, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852, Japan. E-mail: neuro@net.nagasaku.ac.jp between these EEG changes and patients' surgical outcome has not been clarified, in part because of a lack of quantitative data on the EEG changes. Therefore we analyzed the degree of bilateral synchrony and morphologic similarity o...

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