Fibrous Dysplasia: An Epidemiological and Correlational Evaluation of Multimodal Data

Fibrous dysplasia is a benign, pseudotumoral, genetic but non-hereditary condition characterized by the presence of one or more areas of abnormal bone development in which the normal structure is replaced by fibrous tissue. It is an extremely heterogeneous condition, as it can be monostotic, polyostotic, or panostotic, or it may occur within the context of more complex syndromes such as McCune-Albright syndrome (in which polyostotic fibrous dysplasia is associated with café-au-lait spots and precocious puberty) or Mazabraud syndrome (in which intramuscular myxomas are present). This condition is caused by post-zygotic missense mutations, so it is never hereditary, and the affected individual will constitute a so-called "genetic mosaic," a fact that explains the wide variability in the localization of the pathological areas. The mutations in question occur in a gene (GNAS) located on chromosome 20 (20q13.2-13.3); this gene encodes a G protein with GTPase activity, the function of which is consequently impaired. The aim of this study is to evaluate in detail the characteristics of the patients, their hospitalizations, and related interventions. Given the rarity of the condition, such investigations are often conducted on very limited datasets. The present study is expected to include over 200 patients, providing a comprehensive picture. An additional aim is to assess the impact of somatic mutations in the GNAS gene and their impact in terms of clinical manifestations.