1. 2020;23;E281-E288Identification of Candidate Genes Associated with Postherpetic Neuralgia Susceptibility
   Case Control Study
   Xiufang Xing, MD, Yongyu Bai, MD, Kai Sun, MD, Qunshan Chen, MD, Hao Huang, MD, Weidong Qiu, MD, and Min Yan, MD.

BACKGROUND: Postherpetic neuralgia (PHN) is one of the most common complications of herpes zoster (HZ). Heritable factors have been found to play a role in various clinical pain symptoms. However, the effect of gene variability on the susceptibility of PHN remains poorly understood.

OBJECTIVES: The aim of this study was to evaluate whether genetic variation in pain pathway genes was associated with PHN susceptibility in the Chinese population.

STUDY DESIGN: Case–control study.

SETTING: Department of Anesthesiology and Pain Medicine in a university hospital.

METHODS: Seventy patients with PHN and 111 patients with HZ without developing PHN were enrolled. All patients received standardized antiviral agents and analgesics as needed during the acute phase of HZ. Twenty-four candidate genetic polymorphisms in 12 genes (IL1B, SCN9A, KCNK9, TRPV1, P2RX7, HTR1A, HTR2A, ADRB1, ADRB2, BDNF, COMT, and OPRM1) were genotyped in all patients. Multivariable logistic regression analyses were used to identify genetic variations associated with PHN susceptibility while controlling for potential confounders.

RESULTS: Our results suggested that only variation in P2RX7 gene was associated with PHN susceptibility. The P2RX7 rs7958311 AG heterozygous genotype carriers had a decreased risk for PHN in the overdominant model (odds ratio [OR], 0.40; 95% confidence interval [CI], 0.21–0.77; P = 0.005), and codominant model (OR, 0.44; 95% CI, 0.20–0.98; P = 0.045). The P2RX7 rs7958311 GG homozygote genotype was associated with an increased risk for PHN under a recessive model (OR, 2.15; 95% CI, 1.01–4.56; P = 0.046). There were no significant associations between the other 23 single-nucleotide polymorphisms and PHN susceptibility.

LIMITATIONS: Lack of validation cohort to verify the findings.

CONCLUSIONS: In the present study in the Chinese population, we found purinergic receptor P2X7 rs7958311 may contribute to PHN development after HZ. Future larger independent cohorts are warranted to replicate these initial findings.

KEY WORDS: Herpes zoster, postherpetic neuralgia, polymorphisms