Renal manifestations in children with familial Mediterranean Fever

Familial Mediterranean Fever (FMF) is an inherited condition consists of recurrent episodes of inflammation in the abdomen, chest, or joints often accompanied by fever and sometimes a rash or headache. The gene responsible for FMF, MEFV, encodes a protein that is expected to be a down regulator of inflammation. The major renal involvement in FMF is the occurrence of amyloidosis that primarily affects the kidneys and primarily manifests as a nephropathy that passes through consecutive stages of proteinuria, nephrotic syndrome, uremia, end-stage renal failure and death. Association between FMF and non-amyloid glomerulopathies are unusual. It is estimated that about half of the renal involvement in FMF be non-amyloid. Other renal manifestations of FMF includes mesangial proliferative glomerulonephritis (MsPGN),rapid progressive glomerulonephritis (RPGN) ,focal segmental glomerulosclerosis(FSGS) ,membranoproliferative glomerulonephritis(MPGN). We report 2 children who presented with recurrent episodes of fever and abdominal pain and positive test for MEFV gene mutations. One had heterozygous mutation at E148Q and had persistent proteinuria whose renal biopsy showed no deposition of amyloid proteins. Another case had heterozygous mutation at R761H and showed systemic hypertension, hematuria and Nutcracker Syndrome. Our study suggests that in patients with FMF, non-amyloid renal involvements should be considered in the differential diagnosis in addition to amyloidosis