Targeted sequencing of the LRRTM gene family in suicide attempters with bipolar disorder

Am J Med Genet B Neuropsychiatr Genet. 2020 Mar;183(2):128-139. doi: 10.1002/ajmg.b.32767. Epub 2019 Dec 19.

Abstract

Glutamatergic signaling is the primary excitatory neurotransmission pathway in the brain, and its relationship to neuropsychiatric disorders is of considerable interest. Our previous attempted suicide genome-wide association study, and numerous studies investigating gene expression, genetic variation, and DNA methylation have implicated aberrant glutamatergic signaling in suicide risk. The glutamatergic pathway gene LRRTM4 was an associated gene identified in our attempted suicide genome-wide association study, with association support seen primarily in females. Recent evidence has also shown that glutamatergic signaling is partly regulated by sex-related hormones. The LRRTM gene family encodes neuronal leucine-rich transmembrane proteins that localize to and promote glutamatergic synapse development. In this study, we sequenced the coding and regulatory regions of all four LRRTM gene members plus a large intronic region of LRRTM4 in 476 bipolar disorder suicide attempters and 473 bipolar disorder nonattempters. We identified two male-specific variants, one female- and five male-specific haplotypes significantly associated with attempted suicide in LRRTM4. Furthermore, variants within significant haplotypes may be brain expression quantitative trait loci for LRRTM4 and some of these variants overlap with predicted hormone response elements. Overall, these results provide supporting evidence for a sex-specific association of genetic variation in LRRTM4 with attempted suicide.

Keywords: LRRTM4; glutamatergic signaling; haplotype; sex specificity; suicidal behavior.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bipolar Disorder / complications
  • Bipolar Disorder / genetics*
  • Excitatory Amino Acid Agents / metabolism
  • Female
  • Gene Expression / genetics
  • Genetic Predisposition to Disease / genetics
  • Genetic Variation / genetics
  • Genome-Wide Association Study / methods
  • Haplotypes / genetics
  • Humans
  • Leucine-Rich Repeat Proteins
  • Male
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism
  • Polymorphism, Single Nucleotide / genetics
  • Proteins / genetics
  • Proteins / metabolism
  • Suicidal Ideation
  • Suicide / psychology*
  • Suicide / trends
  • Suicide, Attempted / psychology

Substances

  • Excitatory Amino Acid Agents
  • LRRTM1 protein, human
  • LRRTM2 protein, human
  • LRRTM3 protein, human
  • LRRTM4 protein, human
  • Leucine-Rich Repeat Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Proteins