OBJECTIVETo screening mutations of exons 15, 18 and 26 of sodium channel Nav1.7 (SCN9A) gene, and to assess its association with pain related to Parkinsonism.

METHODSRespectively, 101 patients with primary Parkinson's disease (PD) and 104 similar-aged volunteers without PD were recruited from March, 2008 to January, 2011. Mutations of above 3 exons in SCN9A gene was detected with PCR and direct sequencing. For 100 patients with Parkinsonism, the pain was scored with a McGill pain rating scale. Statistical analysis was performed with SPSS.

RESULTSThe prevalence of pain in Parkinsonian was 57%. 43.86% patients with pain were males, and 56.14% were females. Based on Chaudhuri criteria, the pain symptoms may be classified as musculoskeletal pain (10.52%), radicular pain (10.52%), dyskinesis pain (54.38%), pain from akathisia and restlessness (14.04%), dyskinesis combined with radicular pain (5.26%), skeletal muscles pain and headache (1.75%), and arthralgia (3.50%). Two missense mutations were identified, which included 2794A/C (0.941/0.059) (rs12478318) (M932L) in exon 15 and 3448C/T (0.988/0.012) (rs6746030) (R1150W) in exon 18. The wild type A/C for the 2794 locus had a higher prevalence in PD patients with pain, but this was not statistically different. All of the 5 heterozygotes for 3448 (C/T) were found in Parkinsonian patients with pain. No homozygotes were found.

CONCLUSIONThe prevalence of pain was higher in Parkinsonian patients than general population, and the proportion of males to females was similar. More patients have suffered dyskinesis pain. A 3448 (C/T) mutation of SCN9A gene may be related to pathogenesis of pain in Parkinsonism.