Authors: Tracy Forster Kay Chapman John Loughlin
Publish Date: 2004/01/24
Volume: 114, Issue: 4, Pages: 391-395
Abstract
Primary osteoarthritis OA is a common lateonset arthritis that demonstrates a complex mode of transmittance with both jointsite and genderspecific heterogeneity We have previously linkagemapped an OA susceptibility locus to a 12cM interval at chromosome 16p123p121 in a cohort of 146 affected female siblingpair families ascertained by total hip replacement femaleTHR families with a maximum multipoint LOD score of 17 Despite the low LOD score we were encouraged to investigate this interval further following the report of a linkage to the same interval in an Icelandic pedigree with an earlyonset form of hip OA Using public databases we searched the interval for plausible candidates and concluded that the gene encoding the interleukin 4 receptor α chain IL4R was a particularly strong candidate based on its known role in cartilage homeostasis We genotyped nine common single nucleotide polymorphisms SNPs from within IL4R including six nonsynonymous SNPs in the 146 probands from our femaleTHR families stage 1 and in an independent cohort of 310 femaleTHR cases stage 2 We compared allele frequencies with those of 399 agematched female controls All individuals were UK Caucasians The minor alleles of two SNPs demonstrated association in both stages with the most significant association having a Pvalue of 0004 with an odds ratio OR of 21 These two SNPs defined two associated SNP groups Inheriting a minor SNP allele from both groups was a particular risk factor OR=24 P=00008 Our data suggest that functional variants within the IL4R gene predispose to hip OA in Caucasian femalesThis work was funded by Research into Ageing and the Arthritis Research Campaign We thank Professor Andrew Carr and Ms Kim Clipsham who organised the collection of the patient and family samples used in this study We also thank Professor Tim Spector for providing additional female control samples
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