A Rare Genetic Association of an NPHP2 Mutation With Nephronophthisis in a Child With Bombay Blood Group

Nephronophthisis is a rare genetic disorder affecting the kidneys and is one of the leading causes of end-stage kidney disease in children. The Bombay blood group is an extremely rare blood type that poses serious clinical challenges, particularly when managing patients with chronic kidney diseases. This report described a 3-year-old female patient who presented with severe anemia and kidney impairment, which progressed to end-stage kidney disease. During blood grouping, she was unexpectedly identified as having the Bombay phenotype, complicating her anemia management. Genetic testing revealed two novel pathogenic variants: one in the NPHP2 gene, associated with nephronophthisis, and another in the FUT1 gene, which is responsible for the Bombay blood group. The child received treatment involving fluid restriction and diuretic infusions. However, she subsequently progressed to end-stage kidney disease with significant fluid overload and required peritoneal dialysis. Anemia management was achieved through intravenous iron and erythropoiesis-stimulating agents (erythropoietin), eliminating the need for blood transfusions. This case underscores the rare coexistence of nephronophthisis and the Bombay blood group alongside novel mutations, highlighting the critical need for early genetic diagnosis and intervention. It also emphasizes the complexities of managing patients with such rare blood types, which complicate potential transfusion options.