LINGO-2 polymorphism and the risk of Parkinson's disease in Taiwan

''Leucine-rich repeat (LRR) and immunoglobulin (Ig) domain containing, Nogo receptor-interacting protein-1'' also known as LINGO-1 is a protein encoded by the LINGO-1 gene in human. LINGO-1 protein has been demonstrated to play a role in the structural plasticity and integrity of dopaminergic neurons as well as their survival in animal models of Parkinson's disease (PD). The LINGO family includes LINGO-1 to LINGO-4. In two of them, LINGO-1 and LINGO-2 expressions are detectable in the adult mouse brain and appear to be restricted to neuronal tissue. Given the high degree of homology between the LINGO-1 and LINGO-2 proteins, LINGO-1 and its paralog LINGO-2 are reasonable candidate genes for PD. Recently, some variants of LINGO-1 and LINGO-2 have been reported as risk factors for developing PD in some Caucasian populations, but which has not been confirmed in others. In this study we aimed to assess whether the LINGO-2 variant (rs10968280) is associated with PD among Taiwanese. We examined the SNP of LINGO-2 gene (rs10968280 (T > A)) in a total of 457 PD patients (44.9% female) and 378 controls (44.9% female) recruited from neurology clinics at Linkou Chang-Gung Memorial Hospital. The frequencies of rs10968280 genotypes and alleles were similar between the PD and control group. Stratification by age at onset (<50 and ≧50 years) and sex also demonstrated no differences in the minor allele (A) frequency in either cohort. We conclude that the LINGO-2 variant rs109668280 does not contribute to the risk of developing PD in Taiwan.