Linkage and association studies of discoidin domain receptor 1 (DDR1) single nucleotide polymorphisms (SNPs) in juvenile oligoarthritis.
OBJECTIVE
Multiple independent juvenile oligoarthritis susceptibility loci have been identified within the major histocompatibility complex (MHC), including HLA-A, HLA-DRB1 and an as yet unlocalized effect in the centromeric class I region. The discoidin domain receptor 1 (DDR1) gene resides within this region and codes for a receptor tyrosine kinase that plays an important role in regulating cell attachment to collagen, chemotaxis, proliferation and matrix metalloproteinase (MMP) production. DDR1 expression in chondrocytes has not been investigated. The objectives of this study were to investigate expression of DDR1 in healthy chondrocytes and to identify linkage and association of this candidate gene with juvenile oligoarthritis.


METHODS
A set of 135 simplex juvenile idiopathic arthritis families consisting of one affected child and healthy parent(s) and 199 healthy unrelated individuals were genotyped for six single nucleotide polymorphisms (SNPs) within the DDR1 gene using the primer extension SNaPshot trade mark method. Single-point and multipoint transmission disequilibrium tests were carried out with the ETDT and TDTPHASE packages. Allele frequency comparisons between cases and controls were carried out with the chi(2) test. DDR1 expression was investigated in normal articular cartilage by RT-PCR and immunofluorescence methods.


RESULTS
No linkage and association with any of the six SNPs or their haplotypic combinations were observed in the families studied. No significant differences were observed in allele frequencies between patients and controls. DDR1 expression was found in normal articular cartilage by RT-PCR and by immunofluorescence.


CONCLUSIONS
The DDR1 SNPs examined are not involved in susceptibility to juvenile oligoarthritis.
Zeggini
E
E
WTCHG, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK. elez@well.ox.ac.uk
Reginato
A M
AM
Prais
A
A
Thomson
W
W
McLean
W
W
Donn
R
R
D001171:Arthritis, Juvenile / Q000235:genetics*; D002358:Cartilage, Articular / Q000503:physiopathology; D002648:Child; D019902:Chondrocytes / Q000502:physiology; D000070818:Discoidin Domain Receptors; D005455:Fluorescent Antibody Technique / Q000379:methods; D015870:Gene Expression / Q000235:genetics; D005787:Gene Frequency / Q000235:genetics; D008040:Genetic Linkage / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D015810:Linkage Disequilibrium / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D011975:Receptors, Mitogen / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
D011975:Receptors, Mitogen; D000070818:Discoidin Domain Receptors; D020794:Receptor Protein-Tyrosine Kinases