To the Editor: Cystic fibrosis (CF), an autosomal recessive metabolic disease, involves the sweat glands, respiratory system, gastrointestinal system and reproductive systems. Renal amyloidosis secondary to chronic inflammatory stimulus and glomerular changes rarely becomes apparent. An 11-y-old Turkish girl, offspring of a non consanguineous marriage, with CF (diagnosis was made by repeated measurement of high sweat chloride concentrations), who has been followed since the age of 3, presented with respiratory distress. No obvious disease-related mutations were detected (Fig. 1). The patient had a history of frequent hospitalization because of recurrent pulmonary infection. On current admission, hypoalbuminemia (1.5 g/dL), proteinuria (+2) with a urine stick were detected. Daily urinary protein excretion was in the nephrotic range. Morphological and immunohistochemical findings of the kidney biopsy were diagnostic for Amyloid A (AA) amyloidosis. Kidneys are known to be the least affected organs in CF, however in recent years, the incidence of renal disease in patients with CF has been increasing [1–5]. In the study by Castile et al. five of 23 patients who were found to have proteinuria (range, trace to +2) were reviewed in autopsy series, and all of these patients were noted to have renal pathology at autopsy [1]. In another retrospective study, a review of 33 autopsies of patients with CF revealed 33 % amyloidosis, principally in the spleen, liver, and kidney [2]. Glomerular changes occasionally reported in children and teenagers with CF include AA amyloidosis, glomerulosclerosis, deposits of immune complexes, IgA nephropathy with mesangial proliferations, minimal change disease, membranoproliferative glomerulonephritis, fibrillary glomerulonephritis and postinfectious glomerulonephritis [1–4], Yahiaoui et al. identified 13 adult CF patients with renal disease [5]. Renal biopsies of these patients revealed a heterogeneous spectrum of nephropathies. The prognosis of patients with CF and amyloidosis is generally poor; nearly all patients die within 1 y of clinical presentation. Secondary renal amyloidosis, which was determined in our case, is a rare complication of CF. Screening patients with CF for D. Sener (*) Department of Pediatric Infectious Diseases, Istanbul University, Cerrahpasa Medical Faculty, Istanbul 34098, Turkey e-mail: diclesen71@yahoo.com
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