Epigenetic Regulation in Fibrous Dysplasia of Bone: mirDYS Study.

Epigenetic Regulation of Activity and Severity of Fibrous Dysplasia in Bone: mirDYS Study.

Fibrous dysplasia of bone is a rare congenital but non-hereditary disease caused by a post-zygotic activation mutation of the GNAS gene. Patients with fibrous dysplasia may present pain and bone complications (fractures, deformities..) related to their bone lesions.

For undetermined reasons, severity and disease evolution may vary considerably from patient to patient.

Epigenetic regulation could then be involved, including micro Ribonucleic Acids (miRs).

These small non-coding micro Ribonucleic Acids are involved in the regulation of major steps of cellular processes in different pathologies, in particular in bone diseases. However, micro Ribonucleic Acids have never been studied in fibrous dysplasia.

The aim of this study is to identify micro Ribonucleic Acids significantly associated with the severity of fibrous dysplasia.

Inclusion Criteria:

Control population :

• men and women,
• 18 years-old and over,
• consulting a rheumatologist or an orthopedist for arthrosis
• have scheduled surgery for hip or knee replacement surgery or any intervention involving the lower limb or upper limb.

Patients with Fibrous dysplasia:

• men and women,
• 18 years-old and over,
• with a diagnosis of fibrous dysplasia previously established by a rheumatologist.

Exclusion Criteria:

• Refusal to participate in the study
• Long- term corticosteroids treatment (> 3 months)
• Treated osteoporosis
• Chronic inflammatory rheumatism (rheumatoid arthritis, psoriasic arthritis, spondyloarthropathy)
• Collagen disease (osteogenesis imperfecta…)
• Paget's disease, benign bone tumors
• Uncontrolled hypo/hyper-thyroidism, hypo/hyper-parathryoidism
• Severe renal impairment (GFR < 30 ml/min/1.73m2)
• Cancer or bone metastases (current or in the past two years)
• Paget disease, benign bone tumor (osteoid osteoma, enchondroma …)
• Malabsorptive disease (Celiac disease, Whipple's disease, intestinal bypass, short bowel syndrome) and inflammatory bowel disease
• Pregnant women or lactating
• Psychiatric disorders
• Difficulty in understanding French
• Not a beneficiary of french social security
• Patients protected by law