Page 25 - Read Online

Page 8 of 11 Verriello et al. Vessel Plus 2021;5:51 https://dx.doi.org/10.20517/2574-1209.2021.69

Table 4. Acquired amyloid neuropathies and main clinical features
Type of Precursor Organs involved Clinical picture of neuropathy
amyloidosis protein
AL k or λ light Kidney (74%) Length-dependent simmetric sensori-motor axonal polyneuropathy, with
chains Heart (60%) autonomic manifestation
Liver (27%) Carpal tunnel syndrome
Peripheral nervous Atypical manifestation: mono or multicranial neuropathy, mononeuropathies,
system (22%) multiplex mononeuritis, motor neuron diseases, demyelinating
polyradiculoneuropathy
AA Serum amyloid Kidney Peripheral autonomic neuropathy
A protein Neurological
manifestation (rare)
Beta2- β2-protein Kidney Carpal tunnel syndrome
microglobulin Peripheral nervous Autonomic neuropathy
system

been described, associated with elevated CFS protein concentration and nerve root enhancement and
enlargement at MRI examination, according to definite CIDP for EFNS/PNS criteria [50,51] . However,
differently from CIDP patients, subjects affected by AL amyloidosis have prominent autonomic symptoms.

Another important hallmark for AL amyloidosis is CTS, especially if bilateral, which is associated with
peripheral neuropathy. The finding of monoclonal protein associated with axonal neuropathy should
induce the suspicion of AL amyloidosis.

Monoclonal protein includes IgG, IgM, IgA, or light chains only . In 10% of all cases, however, a
[52]
[53]
monoclonal protein is not found . Tissue biopsy (e.g., abdominal fat and sural nerve) should be performed
when AL amyloidosis is highly suspected.

In conclusion, the triad composed by “autonomic features, CTS, and monoclonal proteins” associated with
peripheral neuropathy are the hallmark that should suggest AL amyloidosis diagnosis. Amyloid deposits in
biopsied tissue confirm the diagnosis.

AA amyloidosis
AA amyloidosis is a systemic disease that can develop as a complication of various chronic inflammatory
disorders. Some studies identify obesity and age as predisposing factors . The amyloid fibrils are composed
[54]
of aggregation of serum amyloid A, an acute phase protein, produced by the liver. The kidney is the organ
principally involved. Neurological manifestations are rare, even if cases of peripheral autonomic neuropathy
have been reported .
[55]
B2M associated amyloidosis
B2M associated amyloidosis has been described in patients with chronic kidney disease on long-term
hemodialysis. It is characterized by the accumulation of amyloid fibrils of B2M in the flexor retinaculum,
leading to CTS , in the bones and the joints, causing chronic arthropathy and bone lesions.
[56]

A genetic autosomal dominant form has also been described with Asp76Asn variant B2M, characterized by
progressive gastrointestinal symptoms and autonomic neuropathy. In this case, patients have normal renal
function and normal circulating B2M values, suggesting the fibrillogenicity of the protein in physiological
[57]
conditions .