proportion of patients reported to have renal involvement varies between 20% and 80%. Rapidly progressive glomerulonephritis (RPGN)is rare syndrome in children, characterized by clinical features of glomerulonephritis (GN) and rapid loss of renal function. We present a severe kidney involvement in a 14 year old boy with HSV in who is carring MEFV mutation. A 14 year old boy had developed sudden onset of palpable purpuric rash on his extensor surfaces of lower extremities. He had elevated an erythrocyte sedimentation rate (ESR) (45 mm/h), C-reactive protein (3.74 mg/dl), serum urea 66 mg/dl, serum creatinine 1.8 mg/dl. Also, he had hypocomplementemia