Gene-environment interaction in the onset of eczema in infancy: filaggrin loss-of-function mutations enhanced by neonatal cat exposure.
Author(s)
Type
Journal Article
Abstract
BACKGROUND: Loss-of-function variants in the gene encoding filaggrin (FLG) are major determinants of eczema. We hypothesized that weakening of the physical barrier in FLG-deficient individuals may potentiate the effect of environmental exposures. Therefore, we investigated whether there is an interaction between FLG loss-of-function mutations with environmental exposures (pets and dust mites) in relation to the development of eczema. METHODS AND FINDINGS: We used data obtained in early life in a high-risk birth cohort in Denmark and replicated the findings in an unselected birth cohort in the United Kingdom. Primary outcome was age of onset of eczema; environmental exposures included pet ownership and mite and pet allergen levels. In Copenhagen (n = 379), FLG mutation increased the risk of eczema during the first year of life (hazard ratio [HR] 2.26, 95% confidence interval [CI] 1.27-4.00, p = 0.005), with a further increase in risk related to cat exposure at birth amongst children with FLG mutation (HR 11.11, 95% CI 3.79-32.60, p < 0.0001); dog exposure was moderately protective (HR 0.49, 95% CI 0.24-1.01, p = 0.05), but not related to FLG genotype. In Manchester (n = 503) an independent and significant association of the development of eczema by age 12 mo with FLG genotype was confirmed (HR 1.95, 95% CI 1.13-3.36, p = 0.02). In addition, the risk increased because of the interaction of cat ownership at birth and FLG genotype (HR 3.82, 95% CI 1.35-10.81, p = 0.01), with no significant effect of the interaction with dog ownership (HR 0.59, 95% CI 0.16-2.20, p = 0.43). Mite-allergen had no effects in either cohort. The observed effects were independent of sensitisation. CONCLUSIONS: We have demonstrated a significant interaction between FLG loss-of-function main mutations (501x and 2282del4) and cat ownership at birth on the development of early-life eczema in two independent birth cohorts. Our data suggest that cat but not dog ownership substantially increases the risk of eczema within the first year of life in children with FLG loss-of-function variants, but not amongst those without. FLG-deficient individuals may need to avoid cats but not dogs in early life.
Date Issued
2008-06-24
Date Acceptance
2008-05-06
Citation
PLOS Medicine, 2008, 5 (6)
ISSN
1549-1277
Publisher
Public Library of Science
Journal / Book Title
PLOS Medicine
Volume
5
Issue
6
Copyright Statement
© 2008 Bisgaard et al.
This is an open-access article
distributed under the terms of the
Creative Commons Attribution
License, which permits unrestricted
use, distribution, and reproduction
in any medium, provided the
original author and source are
credited.
This is an open-access article
distributed under the terms of the
Creative Commons Attribution
License, which permits unrestricted
use, distribution, and reproduction
in any medium, provided the
original author and source are
credited.
License URL
Identifier
PII: 07-PLME-RA-1981
Subjects
Age Factors
Age of Onset
Animals
Cats
Codon, Nonsense
Cohort Studies
Dermatitis, Atopic
Dogs
Environment
Environmental Exposure
Gene Expression Regulation
Genetic Predisposition to Disease
Genotype
Humans
Infant
Infant, Newborn
Intermediate Filament Proteins
Parturition
Risk Factors
Publication Status
Published
Article Number
e131