Abdominal fat aspirative biopsy - diagnostic value in familial amyloidotic polyneuropathy, Portuguese type
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文摘
Despite a low incidence in the general population, the different types of systemic amyloidosis (A) are associated with marked morbidity. Several proteins may be involved in the origin of the amyloid fibrills. The different types of A are classified according to the original protein: ligth chain k and λ, serum A protein, β2 microglobulin, Transthyretins (TTR met-30) and others. The final diagnosis is based on the assessment of the tissue organ deposits and identification of the protein with specific antibodies. In the present report we intended to show the value of “abdominal fat aspirative biopsy” (AFAB) in the diagnosis of familial amyloidotic polyneuropathy, Portuguese type (FAP). This assay is easily performed and has a high sensitivity (70 to 80 % ) and specificity (100 % ) when applied to primary and secondary A. It also allows the characterization of amyloid protein using specific antibodies. We have done AFAB in 15 FAP candidates to liver transplantation (mean age = 42 years; mean symptomatic period = 6 years) getting 100 % of sensitivity. Recently we have identified 4 nephrotic patients (P) with no clinical suspicion of A in whom AFAB demonstrated the typical green birrefringency and the subsequent renal biopsies confirmed the diagnosis of A. Specific antibodies against k and λ, serum A protein and β2 microglobulin were systematically negative in these P raising the hypothesis of FAP. In fact, 2 serum samples analysed for TTR met-30 were positive (Centro de Estudo da Paramiloidose - Porto).