Association of NTRK2 gene with suicidality: a meta-analysis

Background
Previous studies have shown that genes in brain development pathways may have important roles in affecting risk of suicidal behaviors, with our previous meta-analysis supporting a role of the brain-derived neurotrophic factor (BDNF) gene. NTRK2 is a gene that encodes the neurotrophic receptor tyrosine kinase 2, which is a receptor for BDNF. In the current study, we aim to examine the potential association between NTRK2 single nucleotide polymorphism (SNPs) and suicidal ideation/behaviors.

Methods
We first conducted a literature search using keywords like ‘NTRK2’, ‘TRKB’, and ‘suicid*’ to identify papers on NTRK2 SNPs and suicidal ideation/behaviors. In addition, we have individual-level genotype data for all the identified SNPs in literature search. We used the R meta package to perform meta-analyses on both the genotype count and the allele count data. Moreover, we performed meta-analyses on specific haplotypes within each haplotype block.

Main results
Following our literature search and meta-analyses on 20 NTRK2 SNPs across up to 8467 samples, we found three SNPs, rs10868235 [N = 5,318, odds ratio (OR) = 1.34, P = 0.02], rs1867283 (N = 5,134, OR = 0.73, P = 0.04), and rs1147198 (N = 5,132, OR = 1.36, P = 0.03) to be nominally associated with suicidal attempts. Those three findings, however, did not survive multiple-testing corrections. Also, none of the haplotype blocks showed significant involvement in suicidality.

Conclusion
Our results suggest that the NTRK2 gene may not have a major role in suicidality. Future efforts, however, should explore gene–gene interaction and pathway analyses.