Autoimmune Polyglandular Syndrome Type 1 (APS-1), or APECED, is a rare autosomal recessive disorder caused by mutations in the AIRE gene, critical for establishing central immune tolerance. We present a case of an 8-year-old female exhibiting classic APS-1 manifestations: chronic mucocutaneous candidiasis, hypoparathyroidism, ectodermal dystrophy, and confirmed AIRE mutation (c.607C>T, p.Arg203Ter). Clinical evaluation revealed hypocalcemia, hyperphosphatemia, low PTH, and vitamin D deficiency. Management included oral calcium and calcitriol with close biochemical monitoring. The case underscores the importance of genetic testing for accurate diagnosis and long-term management. Due to risks of nephrocalcinosis from calcium therapy, renal ultrasound was planned. This report highlights the very rare mutation of AIRE gene which is c.607C>T (p.Arg203Ter) it also highlights the and discusses the potential renal complications in the context of calcium homeostasis. Early identification and targeted management are crucial in preventing disease progression and complications in pediatric APS-1 patients