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Importance: Despite Alzheimer disease (AD) and Parkinson disease (PD) being clinically distinct entities, there is a possibility of a pathological overlap, with some genome-wide association (GWA) studies suggesting that the 2 diseases represent a biological continuum. The application of GWA studies to idiopathic forms of AD and PD have identified a number of loci that contain genetic variants that increase the risk of these disorders., Objective: To assess the genetic overlap between PD and AD by testing for the presence of potentially pleiotropic loci in 2 recent GWA studies of PD and AD., Design: Combined GWA analysis., Setting: Data sets from the United Kingdom, Germany, France, and the United States., Participants: Thousands of patients with AD or PD and their controls., Main Outcomes and Measures: Meta-analysis of GWA studies of AD and PD., Methods: To identify evidence for potentially pleiotropic alleles that increased the risk for both PD and AD, we performed a combined PD-AD meta-analysis and compared the results with those obtained in the primary GWA studies.We also tested for a net effect of potentially polygenic alleles that were shared by both disorders by performing a polygenic score analysis. Finally, we also performed a gene-based association analysis that was aimed at detecting genes that harbor multiple disease-causing single-nucleotide polymorphisms, some of which confer a risk of PD and some a risk of AD., Results: Detailed interrogation of the single-nucleotide polymorphism, polygenic, and gene-based analyses resulted in no significant evidence that supported the presence of loci that increase the risk of both PD and AD., Conclusions and Relevance: Our findings therefore imply that loci that increase the risk of both PD and AD are not widespread and that the pathological overlap could instead be “downstream” of the primary susceptibility genes that increase the risk of each disease.

Purpose of Review: To review and discuss recent studies on molecular diagnosis of peanut and other legume allergy., Recent Findings: Studies from the UK and France suggest that quantification of Ara h 2-specific IgE may accurately discriminate peanut allergy from tolerance. However, the pattern of allergenic component recognition in peanut-sensitized patients from different populations or geographical areas varies, reflecting different pollen and dietary exposures. In the USA, peanut-allergic patients are commonly sensitized to Ara h 1-3, in Spain to Ara h 9 and in Sweden to Ara h 8. Patients with soybean allergy sensitized to Gly m 5 or Gly m 6 allergens may be at greater risk of experiencing severe allergic reactions., Summary: Accurate diagnosis of peanut and legume allergy is challenging and essential. Measurement of IgE response to specific allergenic molecules may be more useful in predicting the presence and severity of clinical allergy than currently used skin or blood tests based on whole extracts. However, given the heterogeneity in component recognition patterns observed in different geographical areas, further studies are essential to identify and confirm potentially useful molecular diagnostic and prognostic markers. Until such markers are confirmed and replicated in different age groups, oral food challenge (OFC) remains the gold standard for accurate diagnosis.