Thauvin-Robinet-Faivre Syndrome: A FIBP Variant in an Adolescent with Segmental Overgrowth and Thyroid Carcinoma.

Overgrowth syndromes are rare genetic disorders arising from alterations in the growth factors pathway. These syndromes can present as generalized overgrowth, characterized by macrosomia and excessive height compared to peers, or partial overgrowth syndromes, where specific body regions exhibit disproportionate growth often accompanied by vascular anomalies. Both forms are associated with an increased risk of tumor development. The fibroblast growth factor 1 (FGF-1) intracellular binding protein (FIBP) gene plays a critical role in cell proliferation and differentiation by interacting with growth factors. In this article, we present a case of Thauvin-Robinet-Faivre syndrome (TROFAS) in a 16-year-old girl, diagnosed with homozygous NM_004214.5 c.412-3_415dup (p. Asp139AIafsTer3) variant in the FIBP gene. This case exhibits phenotypic features and tumor development, including thyroid follicular carcinoma and parotid mucoepidermoid carcinoma, that have not been previously reported in association with this syndrome. Recent studies have implicated FIBP gene defects in overgrowth syndromes, with only a limited number of cases described globally. This case expands the known clinical and tumor spectrum associated with TROFAS, providing new insights into the pathophysiology of this rare disorder.