Parkinson’s disease (PD) in young women is a rare disease. Exposure to manganese fumes from a pottery kiln is a rare disease. Plaintiff Kathleen Gushue, with the help of her expert witnesses, Drs. Paul Nausieda and Elan Louis, argued that the coincidence of both rare exposure and rare outcome must be probative of a causal relationship between the two. Supreme Court Justice Jeffrey K. Oing, realizing that one in million happens eight times a day here in New York City, excluded the proffered testimony of Drs. Nausieda and Louis, and granted defendants summary judgment. Gushue v. Estate of Norman Levy, et al., Supreme Court of New York, New York County, Index No.: 106645/05, Decision & Order (Sept. 28, 2012).
Manganese in very high doses can cause a parkinsonism, but Justice Oing avoided the semantic traps set for him by the plaintiff. Just because PD requires parkinsonism does not mean that manganese-induced parkinsonism can be equated with PD. A dog is a carnivorous mammal, with fur, four legs, and a tail. So is a cat, but a dog is not a cat. Similarly, PD and the specific features of manganese-induced parkinsonism are different. See Agency for Toxic Substances and Disease Registry, Draft Toxicological Profile for Manganese 16 (Draft 2008) (“While manganese neurotoxicity has clinical similarities to Parkinson’s disease, it can be clinically distinguished from Parkinson’s.”); id. at 66-67 (“Manganism and Parkinson’s disease also differ pathologically. * * * It is likely that the terms Parkinson-like-disease and manganese-induced-Parkinsonism will continue to be used by those less knowledgeable about the significant differences between the two.”).
Plaintiff and her expert witnesses also attempted the differential diagnosis ploy, but Justice Oing followed prior New York law that requires a claimant, who is alleging toxic cause, to “reliably rule out reasonable alternative causes of [the alleged harm) or idiopathic causes.” Id., citing Barbaro v Eastman Kodak Co., 26 Misc. 3d 1124 (A) (Sup. Ct., Nassau Cty. 2010) .
Logically and legally, plaintiff could not rule out idiopathic causes that are responsible for the great majority of PD cases. Parkinson’s disease has no known causes other than a few uncommon genetic variants. See John Hardy, “No Definitive Evidence for a Role for the Environment in the Etiology of Parkinson’s Disease,” 21 Movement Disorders 1790 (2006). See also J. Mortimer, A. Borenstein, and L. Nelson, “Associations of welding and manganese exposure with Parkinson disease: Review and meta-analysis,” 79 Neurology 1174 (2012) (reporting a statistically significant decreased risk of Parkinson’s disease among welding tradesmen).
