Nephrology and Dialysis Unit, S. Giovanni Bosco Hospital and University of Turin, Turin, Italy,
Department of Clinical and Biological Sciences, Center of Research of Immunopathology and Rare Diseases, Coordinating Center of the Network for Rare Diseases of Piedmont and Aosta Valley, Department of Clinical and Biological Sciences, University of Turin, Turin, Italy,
Nephron. 2022;146(5):481-488. doi: 10.1159/000522370. Epub 2022 Mar 18.
Transthyretin (TTR) amyloidosis (ATTR) is either an inherited condition or a non hereditary disease due to misfolding of wild-type (WT) TTR. Amyloid deposits can be mainly detected in nerves in the inherited form and in myocardium in the acquired variant. Renal involvement has been described only in the Val30Met mutation of the familial form and is thought to be extremely rare in the WT TTR. However, ATTR is multi-organ disease, and even in the WT forms, apparently limited to the heart, carpal tunnel syndrome and lumbar or cervical spine amyloid deposition have been described. A series of 4 cases of biopsy-proven renal TTR amyloid deposition is reported in the present paper. We describe 2 WT ATTR patients, 1 patient with c.424G>A (p.(Val142Ile)) mutation of the TTR gene, and 1 patient with Val30Met mutation of the TTR gene. In all patients, the biopsy showed the presence of amyloid deposits with different distribution (#1 pericapsular, #2-3 vessels, #4 vessels, interstitium of medulla and cortex, and tubular basement membrane). The use of immunohistochemistry has enabled the identification of TTR, and identify the precursor protein. The possibility of kidney involvement in TTR amyloidosis should be taken into account in patients with renal impairment and unexplained cardiomyopathy and/or neuropathy. This is even of greater interest to the elderly for the possible confounding co-existence of plasma cell dyscrasia that could lead the clinician, in the presence of renal amyloid deposits, to misdiagnose AL amyloidosis and undertake inappropriate treatments.
转甲状腺素蛋白（TTR）淀粉样变（ATTR）是一种遗传性疾病，或是由于野生型（WT）TTR 错误折叠引起的非遗传性疾病。淀粉样沉积物主要可在遗传性形式中在神经中检测到，而在获得性变体中在心内膜中检测到。肾受累仅在家族形式的 Val30Met 突变中被描述，并且在 WT TTR 中被认为极为罕见。然而，ATTR 是多器官疾病，即使在 WT 形式中，也仅在心内膜、腕管综合征和腰椎或颈椎淀粉样沉积中已有报道。本文报告了 4 例经活检证实的肾 TTR 淀粉样变沉积的病例。我们描述了 2 例 WT ATTR 患者，1 例患者的 TTR 基因 c.424G>A（p.（Val142Ile））突变，1 例患者的 TTR 基因 Val30Met 突变。在所有患者中，活检均显示出具有不同分布的淀粉样沉积物（#1 包膜下，#2-3 血管，#4 血管，髓质和皮质间质以及管状基底膜）。免疫组织化学的使用使能够识别 TTR，并鉴定前体蛋白。在患有肾功能不全和不明原因的心肌病和/或神经病的患者中，应考虑 TTR 淀粉样变的肾脏受累的可能性。对于可能存在的浆细胞异常的老年人而言，这更为重要，浆细胞异常可能导致临床医生在存在肾淀粉样变沉积时误诊为 AL 淀粉样变并进行不适当的治疗。
