Case report: De novo mutation of a-galactosidase A in a female patient with end-stage renal disease: report of a case of late diagnosis of Anderson–Fabry disease

Background: Anderson-Fabry disease (AFD) is an X-linked disease that results from reduced activity of the enzyme galactosidase alpha (GLA). When the GLA gene sequence is altered by mutations that alter the normal DNA sequence, variants of the alpha-galactosidase A enzyme are produced, which may or may not function. These mutations are responsible for Fabry disease, and to date, over 800 different mutations of the gene have been described in patients with Anderson-Fabry disease. In this case, we report the case of a woman who is the sole family member with this type of mutation.Case presentation: We report a case of a 52-year-old woman with end-stage chronic kidney disease in dialysis treatment. The patient's alpha-galactosidase activity was 6.6 nmol/ml/h in whole blood, and lyso-GB3 levels were 11.45 nmol/L (normal range < 2.3 nmol/L). Alpha-galactosidase A gene sequence analysis revealed a pathogenic variant of c.947dupT in exon 6, leading to the p. I317NfsTer16 amino acid substitution. The genetic analysis did not detect the same mutation in any of the other screened family members.Conclusion: The international Fabry disease genotype-phenotype database (dbFGP) reports a pathogenic variant c.947dupT in exon 6 that is probably associated with a classical phenotype of Fabry disease. In this case report, we report the case of a woman who is the sole family member with this type of pathogenic variant. Similar situations have not been described in the literature for this pathogenic variant, and it represents an important case of inter- and intrafamilial variability in patients with Fabry disease. The literature shows that de novo pathogenic variants are frequently found in the context of Fabry disease

Fabry disease in W162C mutation: a case report of two patients and a review of literature

BACKGROUND: Fabry disease is a multisystemic disorder characterized by deposition of globotriaosylceramide (Gb3) and its deacylated form in multiple organs, sometimes localized in specific systems such as the nervous or cardiovascular system. As disease-modifying therapies are now available, early diagnosis is paramount to improving life quality and clinical outcomes. Despite the widespread use of non-invasive techniques for assessing organ damage, such as cardiac magnetic resonance imaging (MRI) for patients with cardiac disease, organ biopsy remains the gold standard to assess organ involvement. CASE PRESENTATION: The cases of two patients, father and daughter with a W162C mutation, are described. The father presented with late-onset, cardiac Fabry disease, subsequently developing systolic dysfunction and heart failure. His daughter, while asymptomatic and with normal cardiac assessment (except for slightly reduced native T1 values by cardiac MRI), had already initial myocyte Gb3 deposits on the endomyocardial biopsy, allowing her to start therapy precociously and potentially modifying the course of her disease. A review of the literature concerning the W162C mutation is then provided, showing that it is usually associated to classic, multisystemic Fabry disease rather than the cardiac-restricted form as in these two cases. CONCLUSIONS: Three main points can be concluded from this report. First, the W162C mutation can present with a more variegate phenotype than that predicted on a molecular basis. Second, endomyocardial biopsy was shown in this case to precede non-invasive investigation in determining organ involvement, justifying further studies on this potentially reliable technique, Third, difficulties can arise in the management of asymptomatic female carriers

A comparative blind study between skin biopsy and seed amplification assay to disclose pathological α-synuclein in RBD

To compare the diagnostic accuracy of the immunofluorescence (IF) technique and aSyn-seed amplification assay (aSyn-SAA) of skin and cerebrospinal fluid (CSF) in disclosing pathological α-syn in idiopathic idiopathic REM sleep behavior disorder (iRBD) as early phase of a synucleinopathy. We prospectively recruited 41 patients with iRBD and 40 matched clinical controls including RBD associated with type 1 Narcolepsy (RBD-NT1, 21 patients), iatrogenic causes (2 pt) or OSAS (6 pt) and 11 patients with peripheral neuropathies. IF from samples taken by skin biopsy and aSyn-SAA from skin and CSF samples were analysed blinded to the clinical diagnosis. IF showed a good diagnostic accuracy (89%) that was lower in the case of skin and CSF-based aSyn-SAA (70% and 69%, respectively) because of a lower sensitivity and specificity. However, IF showed a significant agreement with CSF aSyn-SAA. In conclusion, our data may favor the use of skin biopsy and aSyn-SAA as diagnostic tools for a synucleinopathy in iRBD

Clinical and pathology characterization of small nerve fiber neuro(no)pathy in cerebellar ataxia with neuropathy and vestibular areflexia syndrome

Background and purpose: Biallelic mutation/expansion of the gene RFC1 has been described in association with a spectrum of manifestations ranging from isolated sensory neuro(no)pathy to a complex presentation as cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS). Our aim was to define the frequency and characteristics of small fiber neuropathy (SFN) in RFC1 disease at different stages. Methods: RFC1 cases were screened for SFN using the Neuropathic Pain Symptom Inventory and Composite Autonomic Symptom Score 31 questionnaires. Clinical data were retrospectively collected. If available, lower limb skin biopsy samples were evaluated for somatic epidermal and autonomic subepidermal structure innervation and compared to healthy controls (HCs). Results: Forty patients, median age at onset 54 years (interquartile range [IQR] 49–61) and disease duration 10 years (IQR 6–16), were enrolled. Mild-to-moderate positive symptoms (median Neuropathic Pain Symptom Inventory score 12.1/50, IQR 5.5–22.3) and relevant autonomic disturbances (median Composite Autonomic Symptom Score 31 37.0/100, IQR 17.7–44.3) were frequently reported and showed scarce correlation with disease duration. A non-length-dependent impairment in nociception was evident in both clinical and paraclinical investigations. An extreme somatic denervation was observed in all patients at both proximal (fibers/mm, RFC1 cases 0.0 vs. HCs 20.5, p < 0.0001) and distal sites (fibers/mm, RFC1 cases 0.0 vs. HCs 13.1, p < 0.0001); instead only a slight decrease was observed in cholinergic and adrenergic innervation of autonomic structures. Conclusions: RFC1 disease is characterized by a severe and widespread somatic SFN. Skin denervation may potentially represent the earliest feature and drive towards the suspicion of this disorder

A longitudinal skin biopsy study of phosphorylated alpha-synuclein in a patient with Parkinson disease and orthostatic hypotension

The aim of our study was to assess the distribution of phosphorylated a-synuclein (p-syn) deposits in a patient affected by early stage Parkinson disease and orthostatic hypotension through a longitudinal skin biopsy study. We found widespread p-syn spatial diffusion from deep autonomic dermis nerve bundles to autonomic terminals, suggesting a centrifugal spread of p-syn from ganglia to the innervation target structures. Furthermore, the case suggests the possibility of discriminating synucleinopathies at an early stage of disease by means of skin biopsy. If confirmed, these data support skin biopsy as a useful and promising tool for the diagnosis, longitudinal evaluation, and pathological understanding of Parkinson disease

The autonomic innervation of hairy skin in humans: an in vivo confocal study

The autonomic innervation of the skin includes different subsets of adrenergic and cholinergic fibers both in humans and animals. The corresponding chemical code is complex and often difficult to ascertain. Accordingly, a detailed histochemical description of skin autonomic fiber subtypes is lacking in humans. To characterize skin autonomic nerve subtypes may help to better understand the selective damage of specific skin autonomic fibers affecting human diseases such as the adrenergic fibers directed to skin vessels in Parkinson’s disease or the cholinergic sudomotor fibers in Ross Syndrome. The present study aimed at characterizing subtypes of autonomic fibers in relation to their target organs by means of an immunofluorescent technique and confocal microscopy. We studied 8 healthy subjects (5 males and 3 females) aged 45 ± 2 (mean ± SE) years without predisposing causes for peripheral neuropathy or autonomic disorders. They underwent skin biopsy from proximal (thigh) and distal (leg) hairy skin. A combination of adrenergic (i.e. tyrosine-hydroxylase- TH and dopamine beta-hydroxylase- DbH) and cholinergic (vesicular acetylcholine transporter- VACHT) autonomic markers and neuropeptidergic (i.e. neuropeptide Y- NPY, calcitonin gene-related peptide- CGRP, substance P- SP, and vasoactive intestinal peptide- VIP) markers were used to characterize skin autonomic fibers. The analysed skin autonomic structures included: 58 sweat glands, 91 skin arterioles and 47 arrector pili muscles. Our results showed that all skin structures presented a sympathetic adrenergic but also cholinergic innervation although in different proportions. Sympathetic adrenergic fibers were particularly abundant around arterioles and arrector pili muscles whereas sympathetic cholinergic fibers were mainly found around sweat glands. Neuropeptides were differently expressed in sympathetic fibers: NPY were found in sympathetic adrenergic fibers around skin arterioles and very seldom sweat glands but not in adrenergic fibers of arrector pili muscles. By contrast CGRP, SP and VIP were expressed in sympathetic cholinergic fibers. Cholinergic fibers expressing CGRP, SP or VIP without TH or DbH staining were found in arterioles and arrector pili muscles and they likely represent parasympathetic fibers. In addition, all skin structures contained a small subset of neuropeptidergic fibers devoid of adrenergic and cholinergic markers with a likely sensory function. No major differences were found between males and females and proximal and distal sites. In summary hairy skin contains sympathetic adrenergic and cholinergic fibers differently distributed around skin structures with a specific distribution of neuropeptides. The autonomic skin innervation also contains a small amount of fibers, likely to be parasympathetic and sensory

Reader response: Diffuse Lewy body disease manifesting as corticobasal syndrome: A rare form of Lewy body disease

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