ALECT2 Amyloidosis in a Patient Presenting with Rapidly Progressive Focal ANCA-Associated Crescentic Glomerulonephritis: A Case Report

ALECT2 amyloidosis is a systemic amyloidosis derived from the precursor protein leukocyte cell–derived chemotactic 2 (LECT2), which is primarily produced by hepatocytes. ALECT2 has emerged as a prevalent non-AL renal amyloid subtype, especially in older patients of Mexican/Hispanic ancestry, as well as in Punjabi, First Nations, Native American, Egyptian, Sudanese, and Chinese populations. Renal involvement by ALECT2 can clinically mimic other nephritides, primarily with worsening renal function, and has been reported in patients presenting with pulmonary-renal syndromes and systemic lupus erythematosus (SLE). However, concurrent ALECT2 and biopsy proven ANCA-associated crescentic glomerulonephritis (GN)is exceedingly rare. Here we present an 80-year-old Persian male with a previous history of renal dysfunction attributed to urologic issues who presented with rapid deterioration of renal function. Renal biopsy revealed a focal pauci-immune necrotizing and crescentic GN with dual MPO & PR3 antibody positivity superimposed on an unexpected finding of early ALECT2 amyloidosis with atypical glomerular-limited involvement. Here, we discuss treatment responses and considerations of assessment of contributions of each disease to his renal dysfunction.