IL13RA2 gene polymorphisms are associated with systemic sclerosis.
OBJECTIVE
To investigate the influence of genetic variability on the phenotypic expression of systemic sclerosis (SSc), by testing possible associations between single nucleotide polymorphisms (SNP) in IL13RA1 and IL13RA2 genes and SSc in a Caucasian population.


METHODS
As IL13RA1 and IL13RA2 are located on the X chromosome and SSc occurs far more frequently in women than in men, only women were genotyped. The study group comprised 97 women with SSc, 36 with diffuse (dcSSc) and 61 with limited (lcSSc) cutaneous forms of disease, and 109 healthy controls. Patients and controls were Caucasian. We investigated 4 SNP in IL13RA1 and 3 in IL13RA2 by polymerase chain reaction amplifications and enzymatic digestion or primer extension reactions and denaturing high-performance liquid chromatography.


RESULTS
We detected an association between IL13RA2 rs638376 and patients with SSc [p = 0.004, odds ratio (OR) = 1.85, confidence interval (CI) 1.22-2.74, p corr = 0.02], as well as with dcSSc in that subgroup of patients (p = 0.01, OR 2.22, 95% CI 1.27-3.89, p corr = 0.05). The IL13RA2 rs638376G allele frequency was higher in patients with SSc (51.6%) than in controls (36.4%, p = 0.003, OR 1.86, 95% CI 1.24-2.79, p corr = 0.015) and in the subgroup with dcSSc (57.6%) than in controls (36.4%, p = 0.003, OR 2.37, 95% CI 1.35-4.15, p corr = 0.015). One other IL13RA2 SNP was only associated with the dcSSc subgroup: the IL13RA2 rs5946040G allele was more common in patients with dcSSc (33.8%) than in controls (17%, p = 0.004, OR 2.5, 95% CI 1.36-4.60, p corr = 0.02).


CONCLUSIONS
Our data suggest that IL13RA2 gene polymorphisms may be involved in susceptibility to SSc. Further studies are under way to show that they contribute to disease.
Granel
Brigitte
B
Laboratoire d'Immunologie et de Génétique des Maladies Parasitaires, Université de la Méditerranée - Faculté de Médecine de La Timone, 27 boulevard Jean Moulin, 13385 Marseille Cedex 05, France. brigitte.granel@medecine.univ-mrs.fr
Allanore
Yannick
Y
Chevillard
Christophe
C
Arnaud
Violaine
V
Marquet
Sandrine
S
Weiller
Pierre-Jean
PJ
Durand
Jean-Marc
JM
Harlé
Jean-Robert
JR
Grange
Claire
C
Frances
Yves
Y
Berbis
Philippe
P
Gaudart
Jean
J
de Micco
Philippe
P
Kahan
André
A
Dessein
Alain
A
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D053661:Interleukin-13 Receptor alpha1 Subunit / Q000235:genetics; D053663:Interleukin-13 Receptor alpha2 Subunit / Q000235:genetics*; D008875:Middle Aged; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D012595:Scleroderma, Systemic / Q000235:genetics*; D044465:White People / Q000235:genetics
C508181:IL13RA1 protein, human; D053661:Interleukin-13 Receptor alpha1 Subunit; D053663:Interleukin-13 Receptor alpha2 Subunit