Patterns of myelinated nerve fibers loss in transthyretin amyloid polyneuropathy and mimics

Abstract

Objective The present study was intended to analyze the characteristics of myelinated nerve fibers density (MFD) of transthyretin amyloid polyneuropathy (ATTR‐PN) and other similar neuropathies. Methods A total of 41 patients with ATTR‐PN, 58 patients of other common peripheral neuropathies, and 17 age‐and gender‐matched controls who visited the First Hospital of Peking University and performed sural nerve biopsy between June 2007 and August 2021 were included for analysis of MFD. Results Except the vasculitic neuropathy group, the total and small MFD of patients in the ATTR‐PN group were significantly lower than those of other disease groups. There was an obvious negative correlation between the total MFD and the disease course in the ATTR‐PN group. The disease course of early‐onset and late‐onset symptoms was similar, but the loss of large myelinated nerve fibers (MF) was more severe for the latter. In addition, all late‐onset and most early‐onset patients had severely reduced MFD after a 2 years' disease course. The MFD in ATTR‐PN patients was negatively correlated with Neuropathy Impairment Score (NIS) and Norfolk Quality of life‐diabetic neuropathy (Norfolk QOL‐DN) score. Conclusion MF is lost differently in ATTR‐PN and in other common peripheral neuropathies. The late‐onset and early‐onset ATTR‐PN patients have different patterns of loss of large and small MF.

CIDP/autoimmune nodopathies with nephropathy: a case series study

“…All the patients had sural nerve biopsies performed. Sural nerve biopsies were performed as described previously 24 . The specimens were divided into two parts: one was fixed in 4% formalin before being embedded in paraffin and stained with hematoxylin and eosin (HE), luxol fast blue (LFB) and Congo red.…”

“…Sural nerve biopsies were performed as described previously. 24 The specimens were divided into two parts: one was fixed in 4% formalin before being embedded in paraffin and stained with hematoxylin and eosin (HE), luxol fast blue (LFB) and Congo red. The other was fixed in 3% glutaraldehyde and 1% osmium tetroxide and embedded in Epon‐812 after dehydration.…”

Hereditary transthyretin amyloidosis: a comprehensive review with a focus on peripheral neuropathy

“…Although axonal damage is the most reported feature, demyelination has also been described and may lead to misdiagnosis with other acquired or hereditary polyneuropathies ( 95 ).…”

“…In nerve conduction studies, reduced sensory conduction velocity of the median and ulnar nerves was more frequent in ATTRv ( 120 ). In Du et al study, the pattern of myelinated nerve fiber density (MFD) in sural nerve biopsies of 41 ATTRv patients was compared to other neuropathies ( 95 ). MFD was milder in CIDP than ATTRv, with a slower MFD reduction per year ( 95 ).…”

“…In Du et al study, the pattern of myelinated nerve fiber density (MFD) in sural nerve biopsies of 41 ATTRv patients was compared to other neuropathies ( 95 ). MFD was milder in CIDP than ATTRv, with a slower MFD reduction per year ( 95 ). Overall, differentiating ATTRv from CIDP may be challenging, but severe neuropathic pain and dysautonomia should raise suspicion for ATTRv.…”