The enamel renal syndrome (ERS) is a rare disorder featured by amelogenesis imperfecta, gingival fibromatosis and nephrocalcinosis. Gingival fibromatosis is a hallmark of the disease; it is characterized by the accumulation of a collagen-rich, dense connective tissue and of mineral deposits throughout the gingiva. ERS is caused by biallelic mutations in the FAM20A gene encoding a pseudokinase, likely acting as an allosteric activator of FAM20C, the Golgi casein kinase. How mutations in FAM20A may modify the gingival connective tissue homeostasis and cause fibromatosis is currently unknown. Conditioned media of gingival fibroblasts (GF) obtained from four unrelated ERS patients carrying distinct mutations and three control subjects were used. Secretomic analysis identified 109 dysregulated proteins whose abundance had increased (69 proteins) or decreased (40 proteins) at least 1.5-fold compared to control GF. Gene Ontology (GO) analysis revealed biological processes significantly over-represented or under-represented in the ERS GF. Proteins over-represented were mainly involved in extracellular matrix organization, collagen fibril assembly, and biomineralization whereas those under-represented were extracellular matrix-associated proteins. Accordingly, GO disease analysis indicated un significant enrichment of tumoral angiogenesis and fibrosis.