IgA Nephropathy Concomitant with Karyomegalic Interstitial Nephritis

ABSTRCT Immunoglobulin A (IgA) nephropathy is one of the most common glomerulonephritis characterized by the deposition of IgA in glomerular mesangium. Karyomegalic interstitial nephritis (KIN) is a rare interstitial nephritis with potential hereditary factors. IgA nephropathy concomitant with KIN has not yet been reported. Herein, we describe the clinical course, ultrasonic images, and gastrointestinal endoscopy findings of a 28-year-old-male patient with IgA nephropathy with KIN. The pathological examination of the renal biopsy specimen demonstrated mild mesangial proliferative IgA nephropathy with KIN. Molecular genetic testing detected an abnormality in FAN1 gene. The heterozygous mutation was present on chromosome 15q13.3. However, IgA nephropathy with KIN is a rare disorder, and its pathogenesis is yet to be clarified.