CX3CR1 is a modifying gene of survival and progression in amyotrophic lateral sclerosis

PLoS One. 2014 May 7;9(5):e96528. doi: 10.1371/journal.pone.0096528. eCollection 2014.

Abstract

The objective of this study was to investigate the association of functional variants of the human CX3CR1 gene (Fractalkine receptor) with the risk of Amyotrophic Lateral Sclerosis (ALS), the survival and the progression rate of the disease symptoms in a Spanish ALS cohort. 187 ALS patients (142 sporadic [sALS] and 45 familial) and 378 controls were recruited. We investigated CX3CR1 V249I (rs3732379) and T280M (rs3732378) genotypes and their haplotypes as predictors of survival, the progression rate of the symptoms (as measured by ALSFRS-R and FVC decline) and the risk of suffering ALS disease. The results indicated that sALS patients with CX3CR1 249I/I or 249V/I genotypes presented a shorter survival time (42.27 ± 4.90) than patients with 249V/V genotype (67.65 ± 7.42; diff -25.49 months 95%CI [-42.79,-8.18]; p = 0.004; adj-p = 0.018). The survival time was shorter in sALS patients with spinal topography and CX3CR1 249I alleles (diff = -29.78 months; 95%CI [-49.42,-10.14]; p = 0.003). The same effects were also observed in the spinal sALS patients with 249I-280M haplotype (diff = -27.02 months; 95%CI [-49.57, -4.48]; p = 0.019). In the sALS group, the CX3CR1 249I variant was associated with a faster progression of the disease symptoms (OR = 2.58; 95IC% [1.32, 5.07]; p = 0.006; adj-p = 0.027). There was no evidence for association of these two CX3CR1 variants with ALS disease risk. The association evidenced herein is clinically relevant and indicates that CX3CR1 could be a disease-modifying gene in sALS. The progression rate of the disease's symptoms and the survival time is affected in patients with one or two copies of the CX3CR1 249I allele. The CX3CR1 is the most potent ALS survival genetic factor reported to date. These results reinforce the role of the immune system in ALS pathogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Alleles
  • Amyotrophic Lateral Sclerosis / genetics*
  • Amyotrophic Lateral Sclerosis / mortality
  • CX3C Chemokine Receptor 1
  • Disease Progression
  • Female
  • Genetic Predisposition to Disease*
  • Genotype*
  • Haplotypes
  • Humans
  • Male
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • Receptors, Chemokine / genetics*
  • Spain
  • Survival Rate

Substances

  • CX3C Chemokine Receptor 1
  • CX3CR1 protein, human
  • Receptors, Chemokine

Grants and funding

The research of JVT, NM and MJR was supported by grants SAF2008-01902 and IPT-010000-2010-35 from the Spanish Ministerio de Ciencia e Innovación (Micinn), and by a 2009SGR1380 grant from the Generalitat de Catalunya. MM and ES were supported by grant BFU2010-17537 from Micinn. ALL holds a fellowship from the Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). JG was supported by Spanish Fondo de Investigaciones Sanitarias grants (PI10-01070-FEDER and FIS PI13-01272). This work was supported by a Marató de TV3 grant. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.