PAINDYS_Characterizing Pain in Fibrous Dysplasia of Bone/McCune-Albright Syndrome: an Exploratory Pilot Study

NCT07476768 | Not Yet Recruiting

• 1 other identifier: RBHP 2025 PICKERING_ME 3
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

Fibrous dysplasia of bone (FD) / McCune-Albright syndrome (MAS) is a rare congenital bone disorder affecting one or multiple bones, caused by a mosaic somatic mutation of the GNAS gene. In some cases, it may be associated with endocrine or cutaneous abnormalities. The spectrum of bone disease is broad, ranging from isolated monostotic fibrous dysplasia to complete skeletal involvement. Functional prognosis can be complex due to pain, bone deformities, and fracture risk. The disease may initially be identified through non-specific clinical signs such as pain. Indeed, bone pain has been reported in up to 81% of adults and 49% of children, mainly affecting the lower limbs and the spine, with highly variable pain intensity that does not always correlate with the extent of bone lesions. This pain may persist throughout life and impact patients' daily activities. In the general population, it is well known that chronic musculoskeletal pain following events such as surgery or fractures can be associated with central sensitization, a neurophysiological phenomenon characterized by hyperreactivity of the central nervous system, along with impaired modulation of pain through descending inhibitory pathways, a normally protective mechanism that becomes reduced. The pathophysiology of bone pain in FD/MAS remains poorly studied and poorly understood. The presence of central sensitization, reduced pain modulation, and hypersensitivity to everyday stimuli are rarely described but suggested by the existence of chronic pain often lasting many years. The mixed characteristics of pain experienced (nociceptive, neuropathic, inflammatory, or nociplastic) are also poorly defined. To date, no study has explored pain in FD/MAS using a psychophysical approach in comparison with a control population. Our hypothesis is that patients with FD/MAS exhibit central sensitization with reduced pain modulation. This exploratory pilot study aims to investigate, through psychophysical approaches, the pathophysiological mechanisms underlying pain in FD/MAS.

Conditions

Fibrous Dysplasia of Bone; McCune Albright Syndrome

Keywords

Pain Modulation; Pain; Fibrous Dysplasia; Pain Caracterization; Central pain sensitization

Outcome Measures

Primary Outcomes (1)

• Central sensitization tests, measurement of the Conditioned Pain Modulation (CPM) effect

  The patients are seated, the ATS thermode associated with the Pathway is applied to the dominant forearm. From the baseline value of 32°C, the Pathway delivers a "Pain 60 / Test stimulus" for 10 seconds, and the patient scores the pain on a visual numerical scale from 0 to 100. Then, the Pathway delivers a "Pain 60 / Test stimulus" for 30 seconds, and the patient scores the pain on the same scale. Fifteen minutes after the end of the two stimulations, the patient immersed the non-dominant arm for 60 seconds in a water bath at 46.5°C. Then a second identical sequence of 10 and 30 second stimulations was performed, with the scores recorded after each stimulation on the visual numerical scale from 0 to 100. The CPM effect is measured by taking the difference between the pain scores on the visual numerical scale before and after immersion.

  Visit 1 / Day 1

Secondary Outcomes (17)

• Visual Analog Scale

  Visit 1 - Day 1

• The Brief Pain Inventory Questionnaire (BPI)

  Visit 1 - Day 1

• Measurement of the threshold of sensitivity and pain perception induced by a thermal stimulus (hot and cold) at the Pathway - Médoc®

  Visit 1 - Day 1

• Measurement of mechanical pain thresholds and mechanical temporal summation

  Visit 1 - Day 1

• Pain assessment using the Neuropathic Pain Questionnaire (DN4)

  Visit 1 - Day 1

Study Arms (2)

fibrous dysplasia

EXPERIMENTAL

Other: Visit 1 at the center

healthy volunteer

ACTIVE COMPARATOR

Healthy volunteer matched for age and sex

Other: Visit 1 at the center

Interventions

Visit 1 at the center OTHER

Pain assessment and quality of life evaluation

fibrous dysplasia; healthy volunteer

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• For patients :
• Male or female over 18 years of age with fibrous dysplasia/McCune-Albright syndrome diagnosed by a rheumatologist.
• Mentally and legally able to provide informed consent to participate in the study.
• Affiliated with a health insurance system.
• For healthy volunteers :
• Male or female over 18 years of age.
• Matched to patients by age and sex.
• Mentally and legally able to provide informed consent to participate in the study.
• Affiliated with a health insurance system.

You may not qualify if:

• For patients :
• Medical and/or surgical history considered by the investigator or delegated physician to be incompatible with study procedures (e.g., amputation or physical limitation preventing completion of pain assessment tests).
• Recurrent pain at sites planned for stimulation during thermal and mechanical testing (forearms or palms).
• Presence of anxiety and/or depression defined as Hospital Anxiety and Depression Scale (HADS) score \>11.
• Use of complementary treatments for analgesic purposes (e.g., vitamins, herbal products, cannabinoids).
• Individuals under legal protection (guardianship or trusteeship) or deprived of liberty.
• Pregnant or breastfeeding women.
• Refusal to participate.
• For heathly volunteers :
• Medical and/or surgical history considered by the investigator or delegated physician to be incompatible with study procedures (e.g., amputation or physical limitation preventing completion of pain assessment tests).
• Presence of sleep disorders defined as Pittsburgh Sleep Quality Index (PSQI) score \>5.
• Presence of anxiety and/or depression defined as HADS score \>11.
• Use of complementary treatments for analgesic purposes (e.g., vitamins, herbal products, cannabinoids).
• Individuals under legal protection (guardianship or trusteeship) or deprived of liberty.
• Pregnant or breastfeeding women.

Sponsors & Collaborators

• University Hospital, Clermont-Ferrand: lead

Study Sites (1)

CHU clermont-Ferrand

Clermont-Ferrand, France

Location

MeSH Terms

Conditions

Fibrous Dysplasia of Bone; Fibrous Dysplasia, Polyostotic; Pain

Condition Hierarchy (Ancestors)

Osteochondrodysplasias; Bone Diseases, Developmental; Bone Diseases; Musculoskeletal Diseases; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Lise Laclautre

CONTACT

+33473754963; promo_interne_drci@chu-clermontferrand.fr

Lise Laclautre

CONTACT

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Case control study

Study Record Dates

• First Submitted: March 5, 2026
• First Posted: March 17, 2026
• Study Start: March 1, 2026
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027
• Last Updated: March 17, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

FR (1)