Wilson disease (WD) is an autosomal recessive disorder characterized by the toxic accumulation of copper in a number of organs, particularly the liver and brain. As shown in the accompanying paper, linkage disequilibrium & haplotype analysis confirmed the disease locus to a single marker interval at 13q14.3. Here we describe a partial cDNA clone (pWD) which maps to this region and shows a particular 76% amino acid homology to the Menkes disease gene, Mc1. The predicted functional properties of the pWD gene together with its strong homology to Mc1, genetic mapping data and identification of four independent disease-specific mutations, provide convincing evidence that pWD is the Wilson disease gene.

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.

Wilson disease (WD) is an autosomal recessive disorder of copper transport which map to chromosome 13q14.3. In pursuit of the WD gene, we developed yeast artificial chromosome and cosmid contigs, and microsatellite markers which span the WD gene region. Linkage disequilibrium and haplotype analysis of 115 WD families confined the disease locus to a single marker interval. A candidate cDNA clone was mapped to this interval which, as shown in the accompanying paper, is very likely the WD gene. Our haplotype and mutation analyses predict that approximately half of all WD mutations will be rare in the American and Russian populations.

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Definite MS can be consistently diagnosed by current criteria for adult onset MS in patients with the earliest onset of disease who show peculiar clinical features and natural history. These findings may suggest a reconsideration of current lower limits for MS diagnostic criteria.