Renal involvement in Lysinuric protein intolerance: contribution of pathology to assessment of heterogeneity of renal lesions

Publication date: Available online 11 January 2017
Source:Human Pathology
Author(s): Emmanuel Estève, Pauline Krug, Aurélie Hummel, Jean-Baptiste Arnoux, Olivia Boyer, Anais Brassier, Pascale de Lonlay, Vincent Vuiblet, Stéphanie Gobin, Rémi Salomon, Christine Piètrement, Jean-Paul Bonnefont, Aude Servais, Louise Galmiche
Lysinuric protein intolerance (LPI) is a rare autosomal recessive disease caused by mutations in the SLC7A7 gene encoding the light subunit of a cationic amino acid transporter. Symptoms mimic primary urea cycle defects but dysimmune symptoms are also described. Renal involvement in LPI was first described in the 1980's. In 2007, it appeared that it could concern as much as 75% of LPI patients and could lead to end stage renal disease. The most common feature is proximal tubular dysfunction and nephrocalcinosis but glomerular lesions are also reported. However, very little is known regarding histological lesions associated with LPI. We gathered every kidney biopsy of LPI proven patient in our highly specialized pediatric and adult institution. Clinical, biological and histological informations were analyzed. Five LPI patients underwent kidney biopsy in our institution between 1986 and 2015. Clinically, 4/5 presented with proximal tubular dysfunction and 3/5 with nephrotic range proteinuria. Histology showed unspecific tubulointerstitial lesions and nephrocalcinosis in 3/5 biopsies and marked peritubular capillaritis in one child. Glomerular lesions were heterogeneous: lupus like-full house membranoproliferative glomerulonephritis (MPGN) in one child evolved towards monotypic IgG1kappa MPGN sensitive to immunomodulators. One patient presented with glomerular non AA non AL amyloidosis. Renal biopsy is particularly relevant in LPI presenting with glomerular symptoms for which variable histological lesions can be responsible, implying specific treatment and follow up.



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