Targeted sequencing of <em>DC-STAMP</em> in Paget’s disease of bone — ASN Events
  1. Schedule
  2. Poster Viewing I (odd numbers)
  3. Targeted sequencing of DC-STAMP in Paget’s disease of bone

Targeted sequencing of DC-STAMP in Paget’s disease of bone (#197)

Melanie A Sultana 1 2 , Nathan J Pavlos 3 , John P Walsh 1 4 , Sarah L Rea 1 2
  1. Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, W.A, Australia
  2. Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
  3. School of Biomedical Sciences, University of Western Australia , Nedlands, Western Australia, Australia
  4. School of Medicine and Pharmacology, University of Western Australia, Nedlands, Western Australia, Australia

Paget’s disease of bone (PDB) is a chronic, progressive bone disease characterised by abnormalities in bone-resorbing osteoclasts which lead to focal lesions of woven bone that are prone to fracture and deformity. The disease is thought to have a strong genetic component with up to 40% of patients having an affected first-degree relative. Variants in SQSTM1, which encodes the scaffolding protein p62, are the most prominent and consistent genetic risk factor for the disease. In our Western Australian cohort of families ~25% harbour a SQSTM1 mutation. Much of the heritability of PDB remains unknown, however recent genome-wide association studies identified several additional loci associated with the disease, including a SNP on chromosome 8 close to DC-STAMP which encodes a seven-transmembrane receptor protein thought to be critical for osteoclast fusion. In a subsequent study, screening of a French-Canadian cohort identified a missense change, c.1189C>T, p.Leu397Phe, in DC-STAMP as having a marginal (p=0.09) association with PDB. The mutation affects a residue within a transmembrane domain and is predicted to be deleterious by several in silico predictors. Therefore, we performed targeted sequencing of all 3 exons of DC-STAMP in the 53 SQSTM1-ve PDB families. The p.Leu397Phe variant was the only non-synonymous coding variant found to cosegregate in a family with severe, early-onset disease and was also identified in an additional unrelated affected individual. We generated osteoclast-like cells (OCLs) from peripheral blood mononuclear cells isolated from affected (DC-STAMP+ve) and unaffected (DC-STAMP-ve) family members. Our analysis indicates that a greater number of multinucleated, TRAP+ OCLs formed in cultures expressing the p.Leu397Phe variant than wild-type expressing OCLs. We also observed a higher number of nuclei per OCL in p.Leu397Phe cultures. Future studies will assess the effect of this variant on bone resorption and osteoclast signalling pathways as well as intracellular trafficking of the receptor.