Calbindin 1, fibroblast growth factor 20, and α-synuclein in sporadic Parkinson’s disease
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Parkinson’s disease (PD), one of the most common human neurodegenerative disorders, is characterized by the loss of dopaminergic neurons in the substantia nigra of the midbrain. Our recent case-control association study of 268 SNPs in 121 candidate genes identified α-synuclein (SNCA) as a susceptibility gene for sporadic PD (P = 1.7 × 10−11). We also replicated the association of fibroblast growth factor 20 (FGF20) with PD (P = 0.0089). To find other susceptibility genes, we added 34 SNPs to the previous screen. Of 302 SNPs in a total 137 genes, but excluding SNCA, SNPs in NDUFV2, FGF2, CALB1 and B2M showed significant association (P < 0.01; 882 cases and 938 control subjects). We replicated the association analysis for these SNPs in a second independent sample set (521 cases and 1,003 control subjects). One SNP, rs1805874 in calbindin 1 (CALB1), showed significance in both analyses (P = 7.1 × 10−5; recessive model). When the analysis was stratified relative to the SNCA genotype, the odds ratio of CALB1 tended to increase according to the number of protective alleles in SNCA. In contrast, FGF20 was significant only in the subgroup of SNCA homozygote of risk allele. CALB1 is a calcium-binding protein that widely is expressed in neurons. A relative sparing of CALB1-positive dopaminergic neurons is observed in PD brains, compared with CALB1-negative neurons. Our genetic analysis suggests that CALB1 is associated with PD independently of SNCA, and that FGF20 is associated with PD synergistically with SNCA.
KeywordsDopaminergic Neuron Recessive Model Pairwise Linkage Disequilibrium Analysis Single Linkage Disequilibrium Block Potential Combinational Effect
We are grateful to the PD patients who participated in this study. We also thank Chiyomi Ito, Satoko Suzuki, and Dr. Yoshio Momose for help in performing the study; Drs. Akira Oka, Hidetoshi Inoko, and Katsushi Tokunaga for control samples; and Dr. Jennifer Logan for editing the manuscript. This work was supported by a grant from Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST); by the twenty-first Century COE program and KAKENHI (17019044 and 19590990), both from the Ministry of Education, Culture, Sports, Science, and Technology of Japan; and by the Grant-in-Aid for “the Research Committee for the Neurodegenerative Diseases” of the Research on Measures for Intractable Diseases and Research Grant (H19-Genome-Ippan-001), all from the Ministry of Health, Labor, and Welfare of Japan.
- Myhre R, Toft M, Kachergus J, Hulihan MM, Aasly JO, Klungland H, Farrer MJ (2008) Multiple alpha-synuclein gene polymorphisms are associated with Parkinson’s disease in a Norwegian population. Acta Neurol Scand (in press)Google Scholar