title: Familial Mediterranean fever (FMF) with proteinuria: clinical features, histology, predictors, and prognosis in a cohort of 25 patients.
abstract: OBJECTIVE
  Reactive (AA) amyloidosis may complicate familial Mediterranean fever (FMF), the prototype of autoinflammatory diseases. Thus, proteinuria in FMF is commonly viewed as resulting from amyloidosis, and kidney biopsy is deemed superfluous. However, nephropathy other than amyloidosis has been described in FMF, but its rate and distinctive characteristics are unknown. Our aim was to determine the rate and underlying pathology of FMF-related nonamyloidotic proteinuria and compare its clinical course, demographic, and genetic features to those of FMF-amyloid nephropathy.
  
  
  METHODS
  This study is a retrospective analysis of data from patients with FMF undergoing kidney biopsy for proteinuria above 0.5 g/24 h, over 10 years (2001-2011). Clinical, laboratory, genetic, and pathology data were abstracted from patient files. Biopsies were viewed by an experienced pathologist, as necessary.
  
  
  RESULTS
  Of the 25 patients referred for kidney biopsy, only 15 (60%) were diagnosed with amyloid kidney disease (AKD), and 10 were diagnosed with another nephropathy. The AKD and nonamyloid kidney disease (NAKD) groups were comparable on most variables, but showed distinct characteristics with regard to the degree of proteinuria (6.45 ± 4.3 g vs 2.14 ± 1.6 g, p = 0.006), rate of severe FMF (14 vs 5 patients, p = 0.022), and rate of development of end stage renal disease (73.3% vs 20%, p = 0.015), respectively.
  
  
  CONCLUSIONS
  NAKD is common in FMF and, compared to amyloidosis, it is featured with milder course and better prognosis. Contrary to common practice, it is highly recommended to obtain a kidney biopsy from patients with FMF and proteinuria more than 0.5 g/24 h.
authors.affiliation: From the Institute of Nephrology and Hypertension, Sheba Medical Center, Tel Hashomer; Heller Institute of Medical Research, Sheba Medical Center, Tel Hashomer; Department of Pathology, Sheba Medical Center, Tel Hashomer; Department of Pathology, Hadassah-Hebrew University Medical Center, Jerusalem; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv; The Dr. Pinchas Borenstein Talpiot Medical Leadership Program 2012, Chaim Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Olga
authors.initials: O
authors.lastname: Kukuy
authors.forename: Avi
authors.initials: A
authors.lastname: Livneh
authors.forename: Aharon
authors.initials: A
authors.lastname: Ben-David
authors.forename: Juri
authors.initials: J
authors.lastname: Kopolovic
authors.forename: Alexander
authors.initials: A
authors.lastname: Volkov
authors.forename: Yael
authors.initials: Y
authors.lastname: Shinar
authors.forename: Eliezer
authors.initials: E
authors.lastname: Holtzman
authors.forename: Dganit
authors.initials: D
authors.lastname: Dinour
authors.forename: Ilan
authors.initials: I
authors.lastname: Ben-Zvi
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology* / Q000473:pathology; D000328:Adult; D000686:Amyloidosis / Q000209:etiology* / Q000473:pathology; D001706:Biopsy; D010505:Familial Mediterranean Fever / Q000150:complications* / Q000473:pathology; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011507:Proteinuria / Q000209:etiology* / Q000473:pathology; D012042:Registries / Q000706:statistics & numerical data; D012189:Retrospective Studies
keywords: AMYLOIDOSIS; FAMILIAL MEDITERRANEAN FEVER; PROTEINURIA; RENAL FAILURE