Objective: To screen for polymorphisms in alpha 4 subunit (principal subunit of nAChR) gene (CHRNA4).
Methods: DNA was extracted from leukocytes of all subjects including 100 healthy senior people and 100 patients with Parkinson's disease (PD). The exons and adjacent intron regions of CHRNA4 were amplified with PCR. SNPs were screened by denatured high performance liquid chromatography (DHPLC) techniques and restriction fragment length polymorphisms. Potential mutations were confirmed by sequencing.
Results: Total 10 polymorphisms were detected and identified in coding and adjacent intron regions of nAChR alpha 4 gene, that are 420C/T (0.873/0.127), 870C/T (0.828/0.172), 1440A/C (0.858/0.142), 1860C/T (0.738/0.262), 1890C/T (0.605/0.395), intron 5 +14T/C (0.553/0.447), intron 2 +22G/A (0.873/0.127), intron 3 +182 Del22bp (0.813/0.187), 1758C/T and 1809C/T (reference for coding sequence is GenBank SNPs 000744), of which the last three are novel mutations. PD patients appeared higher frequency of deletion in intron 3+182(0.235) than normal controls (0.140)(P=0.015).
Conclusion: nAChR alpha 4 gene is polymorphic. PD patients take higher frequency of intron3+182 Del 22 bp.