Objective: In animal models and humans, mutations in voltage-dependent calcium channel gamma-2 subunit gene (CACNG2) have been associated with neuronal hyperexcitability, including neuropathic pain. The objective of this study was to determine the allelic and genotypic frequencies of CACNG2 polymorphisms (rs4820242, rs2284015 and rs2284017) and their association with the risk of chronic peripheral neuropathic pain (CPNP) in the Mexican population.
Patients and methods: Single nucleotide polymorphisms (SNPs) were determined by real-time PCR, and allelic and genotypic frequencies were compared between healthy Mexican subjects and CPNP patients. The risk of association of CACNG2 SNPs with the presence of CPNP and its characteristics was evaluated.
Results: The allele G (OR 2.08, p = 0.01) of rs2284015 was observed as a risk factor for developing CPNP. The allele A of rs4820442 showed a risk of association with a history of surgery (OR 3.92, p = 0.04), radiculopathy (OR 4.29, p = 0.0001), bilateral presentation of pain (OR 3.15, p = 0.003), and neuropraxia (OR 0.36, p = 0.01). The allele C of rs2284015 was associated with an increased risk of burning and allodynia. In the analysis of the association of genotype frequencies and inheritance patterns, as well as in the analysis of interaction with sex, a modification of risk was observed.
Conclusions: The allele G of rs2284015 and the AGC haplotype of CACNG2 rs4820242, rs2284015 and rs2284017, regardless of sex and etiology could contribute to the risk of CPNP. Certain alleles and genotypes could constitute severity markers in CPNP with sex-biased effects; however, further studies are required to confirm these observations.