FAM20A is a Golgi-associated pseudokinase that functions as an allosteric activator of FAM20C, a serine/threonine kinase crucial for biomineralization 1. FAM20A forms a complex with FAM20C and enhances its ability to phosphorylate secreted proteins that constitute the extracellular matrix guiding enamel mineral deposition 1. The protein is involved in calcium homeostasis and prevents ectopic calcification through proper phosphorylation of mineralization inhibitors like matrix Gla protein 2. Biallelic loss-of-function mutations in FAM20A cause amelogenesis imperfecta type 1G, also designated enamel-renal syndrome, characterized by severe enamel hypoplasia, gingival fibromatosis, intrapulpal calcifications, and nephrocalcinosis 234. FAM20A dysfunction impairs deciduous dental pulp cell proliferation, migration, and osteogenic differentiation while increasing inflammatory gene expression 5. Mechanistically, FAM20A mutations disrupt BMP signaling pathways and upregulate genes involved in ectopic mineralization in soft tissues 2. Recent bioinformatic studies identified FAM20A as a hub gene with diagnostic value in distinguishing papillary thyroid carcinoma with Hashimoto's thyroiditis background from isolated papillary thyroid carcinoma, with an ROC AUC of 0.825 6. FAM20A is quantifiable in human milk and associates with calcium metabolism proteins 7, suggesting roles beyond dental development.