Summary The classic copper metabolism disorder, Wilson disease (WD), was first defined in 1912. Both early onset presentations in infancy and late onset manifestations in adults > 70 years are now well recognized. Modern biochemical and genetic prevalence studies suggest that WD may be considerably more common than previously appreciated. Early diagnosis of WD is crucial to ensure that patients can be started on adequate treatment but uncertainty remains about the best possible choice of medication. Direct genetic testing for ATP7B mutations is increasingly available to confirm the clinical diagnosis of WD. WD needs to be differentiated from other conditions that present clinically with hepatolenticular degeneration or share biochemical abnormalities with WD, such as reduced serum cerulo plasmin levels. Disordered copper metabolism is also implied in an increasing number of other neurological conditions, including a subtype of axonal neuropathy due to ATP7A mutations, and the common late-onset neurodegenerative disorders Alzheimer’s disease and Parkinson’s disease.

Previous studies have failed to identify mutations in the Wilson's disease gene ATP7B in a significant number of clinically diagnosed cases. This has led to concerns about genetic heterogeneity for this condition but also suggested the presence of unusual mutational mechanisms. We now present our findings in 181 patients from the United Kingdom with clinically and biochemically confirmed Wilson's disease. A total of 116 different ATP7B mutations were detected, 32 of which are novel. The overall mutation detection frequency was 98%. The likelihood of mutations in genes other than ATP7B causing a Wilson's disease phenotype is therefore very low. We report the first cases with Wilson's disease due to segmental uniparental isodisomy as well as three patients with three ATP7B mutations and three families with Wilson's disease in two consecutive generations. We determined the genetic prevalence of Wilson's disease in the United Kingdom by sequencing the entire coding region and adjacent splice sites of ATP7B in 1000 control subjects. The frequency of all single nucleotide variants with in silico evidence of pathogenicity (Class 1 variant) was 0.056 or 0.040 if only those single nucleotide variants that had previously been reported as mutations in patients with Wilson's disease were included in the analysis (Class 2 variant). The frequency of heterozygote, putative or definite disease-associated ATP7B mutations was therefore considerably higher than the previously reported occurrence of 1:90 (or 0.011) for heterozygote ATP7B mutation carriers in the general population (P < 2.2 × 10(-16) for Class 1 variants or P < 5 × 10(-11) for Class 2 variants only). Subsequent exclusion of four Class 2 variants without additional in silico evidence of pathogenicity led to a further reduction of the mutation frequency to 0.024. Using this most conservative approach, the calculated frequency of individuals predicted to carry two mutant pathogenic ATP7B alleles is 1:7026 and thus still considerably higher than the typically reported prevalence of Wilson's disease of 1:30 000 (P = 0.00093). Our study provides strong evidence for monogenic inheritance of Wilson's disease. It also has major implications for ATP7B analysis in clinical practice, namely the need to consider unusual genetic mechanisms such as uniparental disomy or the possible presence of three ATP7B mutations. The marked discrepancy between the genetic prevalence and the number of clinically diagnosed cases of Wilson's disease may be due to both reduced penetrance of ATP7B mutations and failure to diagnose patients with this eminently treatable disorder.

Mutations in PINK1 and parkin cause autosomal recessive parkinsonism, a neurodegenerative disorder characterized by the loss of dopaminergic neurons. To highlight potential therapeutic pathways we have identified factors that genetically interact with parkin/PINK1. Here we report that overexpression of the translation inhibitor 4E-BP can suppress all pathologic phenotypes including degeneration of dopaminergic neurons in Drosophila. 4E-BP is activated in vivo by the TOR inhibitor rapamycin, which we find can potently suppress pathology in PINK1/parkin mutants. Rapamycin also ameliorates mitochondrial defects in cells from parkin-mutant patients. Recently, 4E-BP was shown to be inhibited by the most common cause of parkinsonism, dominant mutations in LRRK2. Here we further show that loss of the Drosophila LRRK2 homolog activates 4E-BP and is also able to suppress PINK1/parkin pathology. Thus, in conjunction with recent findings our results suggest that pharmacologic stimulation of 4E-BP activity may represent a viable therapeutic approach for multiple forms of parkinsonism.

BackgroundHuntington's disease (HD) is a fatal inherited neurodegenerative disease, caused by a