Parkinson disease

Studies have indicated a potential link between Parkinson disease and melanoma, although the nature of this association has remained unknown. Gao et al. prospectively explored this relationship in >150,000 people particpating in two large US cohort studies over a 14–20 year follow-up period. The researchers discovered that a family history of melanoma increased the risk of Parkinsion disease nearly twofold, suggesting that these conditions share common genetic factors. Gao et al. conclude that the genes involved in melanoma could be investigated as potential susceptibility genes for this neurodegenerative disorder.

Neuromuscular disease

Clinicians can be reluctant to vaccinate against influenza in patients with myasthenia gravis for fear of adverse events. The dangers posed by influenza vaccination in such patients, however, have not been determined. Using health-care data from Ontario, Canada, Zinman and colleagues identified 3,667 patients with myasthenia gravis who were admitted to hospital within 42 weeks of influenza vaccination. No difference could be found in the incidence of admission between the primary risk interval (defined as ≤6 weeks post-vaccination) and the control period (6–42 weeks post-vaccination). According to Zinman and colleagues, this finding suggests that influenza vaccination does not exacerbate myasthemia gravis.

Alzheimer disease

The hippocampus is one of a limited number of brain regions that exhibit neurogenesis during adulthood. In Alzheimer disease, the hippocampus exhibits high levels of amyloid-β (Aβ) pathology and neurogeneration, which compromise this neurogenesis. Biscaro et al. report that passive Aβ immunotherapy led to a reduction in Aβ plaque load and an increase in the survival rate of new hippocampal neurons in aged, transgenic Alzheimer disease mice. Moreover, the surving neurons exhibited morphological indicators of functional activity on maturation, and the treatment promoted angiogenesis in the dentate gyrus. On the basis of these results, the researchers suggest that Aβ immunotherapy might be able to improve the deficits in neuronal and vascular function that are exhibited in patients with Alzheimer disease.