Charcot-Marie-Tooth Disease with Myelin Protein Zero Mutation Presenting as Painful, Predominant Small-Fiber Neuropathy.

Charcot-Marie-Tooth disease (CMT) rarely presents with painful symptoms, which mainly occur in association with myelin protein zero (MPZ) gene mutations. We aimed to further characterize the features of painful neuropathic phenotypes in MPZ-related CMT. We report on a 58-year-old woman with a longstanding history of intermittent migrant pain and dysesthesias. Examination showed minimal clinical signs of neuropathy along with mild changes upon electroneurographic examination, consistent with an intermediate pattern, and small-fiber loss upon skin biopsy. Genetic testing identified the heterozygous variant p.Trp101Ter in MPZ. We identified another 20 CMT patients in the literature who presented with neuropathic pain as a main feature in association with MPZ mutations, mostly in the extracellular MPZ domain; the majority of these patients showed late onset (14/20), with motor-nerve-conduction velocities predominantly in the intermediate range (12/20). It is hypothesized that some MPZ mutations could manifest with, or predispose to, neuropathic pain. However, the mechanisms linking MPZ mutations and pain-generating nerve changes are unclear, as are the possible role of modifier factors. This peculiar CMT presentation may be diagnostically misleading, as it is suggestive of an acquired pain syndrome rather than of an inherited neuropathy.

Non-length-dependent small fiber neuropathy: Not a matter of stockings and gloves.

The clinical spectrum of small fiber neuropathy (SFN) encompasses manifestations related to the involvement of thinly myelinated A-delta and unmyelinated C fibers, including not only the classical distal phenotype, but also a non-length-dependent (NLD) presentation that can be patchy, asymmetrical, upper limb-predominant, or diffuse. This narrative review is focused on NLD-SFN. The diagnosis of NLD-SFN can be problematic, due to its varied and often atypical presentation, and diagnostic criteria developed for distal SFN are not suitable for NLD-SFN. The topographic pattern of NLD-SFN is likely related to ganglionopathy restricted to the small neurons of dorsal root ganglia. It is often associated with systemic diseases, but about half the time is idiopathic. In comparison with distal SFN, immune-mediated diseases are more common than dysmetabolic conditions. Treatment is usually based on the management of neuropathic pain. Disease-modifying therapy, including immunotherapy, may be effective in patients with identified causes. Future research on NLD-SFN is expected to further clarify the interconnected aspects of phenotypic characterization, diagnostic criteria, and pathophysiology.

Non-length-dependent somatosensory small fiber pathology presenting with restless legs syndrome in pre-motor Parkinson's disease. Evidence from skin biopsy in four patients.

BACKGROUND: The determinants of restless legs syndrome (RLS) occurring in co-morbid association with Parkinson's disease (PD) are currently unknown. METHODS: We performed a skin biopsy in proximal and distal sites of lower limbs in four PD patients, in which RLS had emerged in the pre-motor phase. RESULTS: A reduced somato-sensory intraepidermal nerve fiber (IENF) density mainly in the proximal sites, indicative of non-length-dependent small fiber pathology (SFP), was found in all patients, in absence of electroneurographic signs of large fiber neuropathy. DISCUSSION: The lack of known secondary causes of SFP is consistent with a process intrinsic to PD and, likewise, the absence of known disease conditions associated to RLS, would support the view of a link between the latter disorder and the distal axonopathy. The non-length-dependent pattern of SFP suggest an involvement of the somato-sensory dorsal root ganglia small neurons, consistent with a somato-sensory neuronopathy, which characterizes the RLS in these patients. CONCLUSION: If these findings will be confirmed in a larger cohort of patients, the RLS co-morbid with PD should be regarded as an heterogeneous condition, since the one emerging in the pre-motor phase might represent a prodromal feature of the neurodegenerative disease as an epiphenomenon of somato-sensory SFP. In contrast, for the RLS developing in clinically manifest PD, a possible association with the impairment of the DAergic diencephalo-spinal pathway and the induction by chronic DAergic treatment has been hypothesized.

Central facial palsy revisited: a clinical-radiological study.

We investigated the pattern of volitional facial motor deficits in acute stroke patients. We assessed the strength of single facial movements and correlated it to the site of infarct classified on computed tomography scans. Exclusion criteria were previous stroke, cerebral hemorrhage, and subcortical stroke. Results showed that weakness in eyelid closure was associated with anterior cerebral artery (ACA) stroke. Weakness in lip opening was associated with middle cerebral artery (MCA) stroke. We suggest that sparing of upper facial movements in MCA stroke is due to the presence of an upper face motor representation in both the MCA and ACA territories.