Bone scan findings of Paget's disease of bone in patients with VCP Multisystem Proteinopathy 1

Area of Science:

• Genetics
• Bone Metabolism
• Neurology

Background:

• Multisystem Proteinopathy 1 (MSP1) is a rare genetic disorder linked to Valosin-Containing Protein (VCP) gene mutations.
• MSP1 presents with a spectrum of symptoms including inclusion body myopathy (IBM), frontotemporal dementia (FTD), and Paget's disease of bone (PDB).
• Early identification of PDB in MSP1 patients is crucial for management and preventing complications.

Purpose of the Study:

• To evaluate the utility of technetium-99m bone scans in screening for PDB in patients with VCP gene mutations.
• To characterize the bone scan findings in MSP1 patients with and without diagnosed PDB.
• To assess the potential for bone scans to identify previously undiagnosed PDB in at-risk individuals.

Main Methods:

• Bone scan imaging was performed on twelve patients with confirmed VCP gene mutations.
• Patients were categorized based on clinical presentation: myopathy alone, myopathy with PDB, and presymptomatic carriers.
• Diagnostic confirmation involved clinical history, biochemical analysis, and skeletal radiographs.

Main Results:

• Two patients with previously undiagnosed PDB showed positive findings on bone scans and subsequent radiographs.
• Increased radiotracer uptake in PDB-affected bones followed typical distributions (thoracic spine, ribs, pelvis, shoulder, calvarium).
• Technetium-99m bone scans demonstrated sensitivity in detecting PDB in MSP1 patients.

Conclusions:

• Technetium-99m bone scans serve as a sensitive screening tool for PDB in patients with MSP1-associated VCP variants.
• Bone scans can identify PDB in individuals with myopathy alone or presymptomatic carriers.
• While sensitive, bone scans require complementary clinical and radiographic data for definitive PDB diagnosis and management in MSP1 patients.