BACKGROUND: Progression of joint destruction in rheumatoid arthritis (RA) is partly heritable; knowledge of genetic factors may increase our understanding of the mechanisms underlying joint... Show moreBACKGROUND: Progression of joint destruction in rheumatoid arthritis (RA) is partly heritable; knowledge of genetic factors may increase our understanding of the mechanisms underlying joint destruction. The activity of the Wnt/β-catenin pathway influences osteoblast differentiation. Dickkopf-1 (Dkk-1) and sclerostin (Sost) are negative regulators and lipoprotein receptor-related protein-5 (LRP-5) and Kremen-1 are transmembrane receptors involved in this pathway. OBJECTIVE: To study variants in the genes encoding these proteins in relation to progression of joint destruction. METHODS: 1418 patients with RA of four cohorts with 4885 sets of hands and feet x-rays were studied. Explorative analyses were performed on 600 patients with RA from Leiden on single nucleotide polymorphisms (SNPs) tagging Dkk-1, Sost, Kremen-1 and LRP-5. SNPs significantly associating with joint damage progression were subsequently genotyped in cohorts from Groningen (NL), Sheffield (UK) and Lund (Sweden). Data were summarised in meta-analyses. Serum levels of functional Dkk-1 and sclerostin were measured and studied in relation to genotypes. RESULTS: In the first cohort, six Dkk-1, three Sost, one Kremen-1 and 10 LRP-5 SNPs were significantly associated with radiological progression of joint destruction. Three Dkk-1 SNPs were associated significantly with progression of joint damage in the meta-analysis, also after correction for multiple testing (rs1896368, rs1896367 and rs1528873). Two Sost SNPs tended to significance (rs4792909 and rs6503475, p=0.07 after false discovery rate correction). Gene-gene interactions between SNPs on Dkk-1 and Sost were seen. Serum levels of Dkk-1 were significantly correlated with the genotypes in rs1896368 (p=0.02). CONCLUSIONS: Patients with RA carrying risk alleles of genetic variants in Dkk-1 have higher serum levels of functional Dkk-1 and more progressive joint destruction over time. Show less
Nies, J.A.B. van; Brouwer, E.; Gaalen, F.A. van; Allaart, C.F.; Huizinga, T.W.J.; Posthumus, M.D.; Helm-van Mil, A.H.M. van der 2012
OBJECTIVE: Only 31% of Dutch rheumatoid arthritis (RA)-patients visit a rheumatologist within 12 weeks after symptom onset; this is mainly due to delay at the level of the general practitioner (GP)... Show moreOBJECTIVE: Only 31% of Dutch rheumatoid arthritis (RA)-patients visit a rheumatologist within 12 weeks after symptom onset; this is mainly due to delay at the level of the general practitioner (GP). In order to reduce delay of GPs in identifying early arthritis, we initiated an Early Arthritis Recognition Clinic (EARC). METHODS: EARCs were initiated at the Leiden and Groningen University Medical Centers. At this EARC, patients filled in a questionnaire about their symptoms, followed by a short visit with only a full joint examination by an experienced rheumatologist. If arthritis was present the patient got an appointment the same week at the regular outpatient clinic. The main outcome parameter was the GP-delay; the secondary outcome parameter was the total delay. In both centres, patients included in early arthritis clinics that had arrived via regular referrals served as control group. RESULTS: Four hundred patients visited the Leiden EARC and 212 patients the Groningen EARC. Arthritis was detected in 42% and 49% respectively. The median GP-delay for these arthritis patients was 2.0 (0.4-7.3) and 2.0 (0.4-10.0) weeks and the median total delay 8.6 (3.6-22.3) and 10.6 (3.1-30.8) weeks respectively. At these two clinics 59% and 51% of all arthritis patients and 65% and 53% of the patients that were subsequently diagnosed with undifferentiated arthritis or RA were seen within 12 weeks after symptom onset. In the Leiden and Groningen control groups that arrived via regular referrals, only 32% and 38% were seen within 12 weeks time. CONCLUSIONS: The EARC increased the early identification of arthritis and RA. Show less
Rooy, D.P.C. de; Kalvesten, J.; Huizinga, T.W.J.; Helm-van Mil, A.H.M. van der 2012
