Wilson disease (WD) is an autosomal recessive disorder characterized by toxic accumulation of copper in the liver and subsequently in the brain and other organs. On the basis of sequence homology to known genes, the WD gene (ATP7B) appears to be a copper-transporting P-type ATPase. A search for ATP7B mutations in WD patients from five population samples, including 109 North American patients, revealed 27 distinct mutations, 18 of which are novel. A composite of published findings shows missense mutations in all exons-except in exons 1-5, which encode the six copper-binding motifs, and in exon 21, which spans the carboxy-terminus and the poly(A) tail. Over one-half of all WD mutations occur only rarely in any population sample. A splice-site mutation in exon 12 accounts for 3% of the WD mutations in our sample and produces an in-frame, 39-bp insertion in mRNA of patients homozygous, but not heterozygous, for the mutation. The most common WD mutation (His1069Glu) was represented in approximately 38% of all the WD chromosomes from the North American, Russian, and Swedish samples. In several population cohorts, this mutation deviated from Hardy-Weinberg equilibrium, with an overrepresentation of homozygotes. We did not find a significant correlation between His1069Glu homozygosity and several clinical indices, including age of onset, clinical manifestation, ceruloplasmin activity, hepatic copper levels, and the presence of Kayser-Fleischer rings. Finally, lymphoblast cell lines from individuals homozygous for His1069Glu and 4 other mutations all demonstrated significantly decreased copper-stimulated ATPase activity.

To define cognitive deficits in children with absence epilepsy. Cognitive deficits have often been reported in children with epilepsy, but have rarely been characterized in patients with a specific epileptic syndrome. Detailed neuropsychological testing was carried out on 16 right-handed children with absence epilepsy with similar clinical and EEG findings, and the findings were compared to 16 well-matched right-handed children without absence epilepsy. The authors found lower scores of measures of general cognitive functioning and visuospatial skills in patients with absence epilepsy, as compared to controls. Memory disturbances were also detected in absence epilepsy patients, with selective involvement of nonverbal memory and delayed recall. In contrast, verbal memory and language skills were relatively preserved. Patients whose seizures began at an earlier age seemed to have more severe cognitive deficits. Language skills tend to be relatively well preserved in children with generalized epilepsy, with more dysfunction seen in global terms rather than specific lateralizing deficits. Patients with absence epilepsy seem to show a similar neurocognitive profile that may be a reflection of the underlying epilepsy syndrome.