Background: Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of chronic kidney disease in children, occurring in 4 to 60 out of 10,000 births. They represent 20-30% of all congenital anomalies, with severity ranging from mild, transient hydronephrosis to kidney failure requiring early dialysis. Approximately 40% of children on kidney replacement therapy in the UK are affected by congenital kidney anomalies, particularly renal hypoplasia or dysplasia. CAKUT encompasses a wide range of phenotypes, including multicystic dysplastic kidney (MCDK) and renal agenesis, with severity often correlating with the timing of developmental disruption. Over 200 syndromes include CAKUT, such as Eagle-Barrett syndrome and PUV. Radiologic studies, especially prenatal ultrasonography, are pivotal for early detection. Genetic testing, particularly for HNF1B and PAX2, is being explored to identify genes implicated in CAKUT, despite limitations in current research strategies. This study aims to further investigate HNF1B mutations in CAKUT to accentuate understanding of its genetic basis and extra-renal clinical manifestations.