Plasma proteomic markers of pain and emotional dysfunction in fibrous dysplasia/McCune-Albright syndrome.

Pain in Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) remains poorly understood and inadequately managed due to uncertainties regarding clinical or biological drivers. This cross-sectional pilot study aimed to use plasma proteomics to identify markers that inform on molecular pathways associated with pain and emotional symptoms in FD/MAS. Seventeen individuals (15 females, 2 males), aged 16 to 63 years, with confirmed diagnoses of monostotic FD, polyostotic FD, or MAS participated in a single study visit conducted at Boston Children's Hospital and Massachusetts General Brigham. During the visit, participants completed validated questionnaires assessing neuropathic pain characteristics, pain interference, anxiety symptoms, depression symptoms, and perceived stress, and provided plasma samples. These samples were analyzed for 57 proteins using Olink proximity extension assay. Associations between protein concentrations and symptom scores were evaluated using Spearman's correlations with false discovery rate correction (|r| > 0.5, p < 0.05). After FDR correction, the concentrations of seven proteins (TNF-α, LTA, CCL19, CSF2, CCL2, CCL4, CCL7) significantly correlated with pain interference, HADS-depression scores, or perceived stress. Four protein concentrations (TNF-α, CCL19, CSF2, CCL7) significantly correlated with multiple clinical measures. This pilot study identified several pain-associated proteins in individuals with FD/MAS, suggesting that proteomic profiling may be a promising approach for discovering pain biomarkers. Larger, longitudinal studies are needed to validate these results and investigate whether targeting immune pathways can alleviate pain and improve emotional health in FD/MAS.