RESUMEN
BACKGROUND: Osteoporosis is diagnosed by the measurement of bone mineral density, which is a highly heritable and multifactorial trait. We aimed to identify genetic loci that are associated with bone mineral density. METHODS: In this genome-wide association study, we identified the most promising of 314 075 single nucleotide polymorphisms (SNPs) in 2094 women in a UK study. We then tested these SNPs for replication in 6463 people from three other cohorts in western Europe. We also investigated allelic expression in lymphoblast cell lines. We tested the association between the replicated SNPs and osteoporotic fractures with data from two studies. FINDINGS: We identified genome-wide evidence for an association between bone mineral density and two SNPs (p<5x10(-8)). The SNPs were rs4355801, on chromosome 8, near to the TNFRSF11B (osteoprotegerin) gene, and rs3736228, on chromosome 11 in the LRP5 (lipoprotein-receptor-related protein) gene. A non-synonymous SNP in the LRP5 gene was associated with decreased bone mineral density (rs3736228, p=6.3x10(-12) for lumbar spine and p=1.9x10(-4) for femoral neck) and an increased risk of both osteoporotic fractures (odds ratio [OR] 1.3, 95% CI 1.09-1.52, p=0.002) and osteoporosis (OR 1.3, 1.08-1.63, p=0.008). Three SNPs near the TNFRSF11B gene were associated with decreased bone mineral density (top SNP, rs4355801: p=7.6x10(-10) for lumbar spine and p=3.3x10(-8) for femoral neck) and increased risk of osteoporosis (OR 1.2, 95% CI 1.01-1.42, p=0.038). For carriers of the risk allele at rs4355801, expression of TNFRSF11B in lymphoblast cell lines was halved (p=3.0x10(-6)). 1883 (22%) of 8557 people were at least heterozygous for these risk alleles, and these alleles had a cumulative association with bone mineral density (trend p=2.3x10(-17)). The presence of both risk alleles increased the risk of osteoporotic fractures (OR 1.3, 1.08-1.63, p=0.006) and this effect was independent of bone mineral density. INTERPRETATION: Two gene variants of key biological proteins increase the risk of osteoporosis and osteoporotic fracture. The combined effect of these risk alleles on fractures is similar to that of most well-replicated environmental risk factors, and they are present in more than one in five white people, suggesting a potential role in screening.
Asunto(s)
Densidad Ósea/genética , Fracturas Óseas/etiología , Proteínas Relacionadas con Receptor de LDL/genética , Osteoporosis/genética , Osteoprotegerina/genética , Polimorfismo de Nucleótido Simple/genética , Alelos , Cromosomas Humanos Par 11 , Cromosomas Humanos Par 8 , Femenino , Expresión Génica , Marcadores Genéticos , Genoma Humano , Genotipo , Humanos , Proteína-5 Relacionada con Receptor de Lipoproteína de Baja Densidad , Vértebras Lumbares , Masculino , Persona de Mediana Edad , Osteoporosis/complicacionesRESUMEN
OBJECTIVE: To examine the association of genetic variation in key players in the Wnt signaling pathway with aspects of osteoarthritis (OA) in two population-based cohort studies: the Rotterdam Study and the Chingford Study. METHODS: Radiographic OA (ROA) was defined as a Kellgren/Lawrence score (K/L) score > or = 2 for the knee and hip. Total hip replacement (THR) was scored. Hand OA was defined as presence of ROA (K/L > or = 2) in two out of three hand joint groups [distal interphalangeal (DIPs), proximal interphalangeal (PIPs), first carpometacarpal (CMC1)/trapezio-scaphoid joint (TS)] of each hand. The concentration of urinary C-terminal cross-linked telopeptide of type II collagen (CTX-II) was standardized to the total urine creatinine. Genotypes for the amino acid variants, Arg200Trp and Arg324Gly of Frizzled-Related protein gene (FRZB), Ala1330Val of Low-density lipoprotein receptor-related protein 5 (LRP5) and Ile1062Val of Low-density lipoprotein receptor-related protein 6 (LRP6), were obtained using the Taqman allelic discrimination assay. A meta-analysis was performed for the FRZB Arg324Gly polymorphism and hip- and knee-OA using RevMan version 4.3. RESULTS: No consistent associations were observed between the FRZB, LRP5 and LRP6 amino acid variants and radiographic hip-, knee-, or hand-OA or THR, in either study population. While power was limited for most studies to date, a meta-analysis of all published studies regarding the FRZB Arg324Gly polymorphism was performed for hip- and knee-OA separately. This showed no significant associations between the Gly324 allele and risk for hip- or knee OA, although there was large heterogeneity between studies for hip OA in females. CONCLUSION: No association was seen between FRZB, LRP5 and LRP6 variants with radiographic osteoarthritic outcomes in two population-based cohorts. In future studies, increased power and standardization of OA-phenotypes are highly recommended for replication studies and to allow meta-analysis.
Asunto(s)
Glicoproteínas/genética , Articulaciones/metabolismo , Proteínas Relacionadas con Receptor de LDL/genética , Osteoartritis/genética , Receptores de LDL/genética , Anciano , Femenino , Predisposición Genética a la Enfermedad , Glicoproteínas/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular , Proteínas Relacionadas con Receptor de LDL/metabolismo , Proteína-5 Relacionada con Receptor de Lipoproteína de Baja Densidad , Proteína-6 Relacionada a Receptor de Lipoproteína de Baja Densidad , Masculino , Persona de Mediana Edad , Países Bajos/epidemiología , Osteoartritis/diagnóstico por imagen , Osteoartritis/epidemiología , Polimorfismo Genético/genética , Radiografía , Receptores de LDL/metabolismo , Transducción de Señal/genética , Reino Unido/epidemiologíaRESUMEN
Expression of death-signaling genes induces many biochemical cascades resulting in elimination of cells via apoptosis or programmed cell death. GC79/TRPS1 is a novel apoptosis associated gene that encodes a multitype zinc finger GATA-type transcription factor. Expression of GC79/TRPS1 is repressed in the rat ventral prostate and significantly elevated after androgen withdrawal by castration. Castration leads to regression of the prostate caused by apoptosis of androgen-dependent prostate cells. Prostate cancer consists of androgen-dependent and androgen-independent cells. The androgen-independent cells, usually present in the prostate of advanced prostate cancer patients do not have the ability to undergo apoptosis after androgen withdrawal. GC79/TRPS1 expression in androgen-dependent prostate cancer cells is repressed by androgens, while GC79/TRPS1 expression is hardly detectable in androgen-independent prostate cancer cells under cell culture conditions. This suggests that lack of GC79/TRPS1 expression could be a mechanism for the inability to induce the apoptotic pathway in androgen-independent prostate cancer cells after androgen withdrawal. This review will focus on the current knowlegde of the structure and function of GC79/TRPS1, a novel androgen-repressible apoptosis gene.