RFC1 AAGGG repeat expansion masquerading as Chronic Idiopathic Axonal Polyneuropathy.

BACKGROUND: A biallelic intronic AAGGG repeat expansion in the Replication Factor C subunit 1 (RFC1) gene has been recently associated with Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome, a disorder often presenting as a slowly evolving sensory neuropathy at the onset. "Chronic Idiopathic Axonal Polyneuropathy" (CIAP) is a common indolent axonal neuropathy of adulthood which remains without an identifiable cause despite thorough investigations. METHODS: We screened 234 probands diagnosed with CIAP for a pathogenic biallelic RFC1 AAGGG repeat expansion. Patients were selected from 594 consecutive patients with neuropathy referred to our tertiary-care center for a sural nerve biopsy over 10 years. RESULTS: The RFC1 AAGGG repeat expansion was common in patients with pure sensory neuropathy (21/40, 53%) and less frequent in cases with predominantly sensory (10/56, 18%, P < 0.001) or sensorimotor (3/138, 2%, P < 0.001) neuropathy. The mutation was associated with sensory ataxia (τb = 0.254, P < 0.001), autonomic disturbances (35% vs 8%, Prevalence Odds Ratio-POR 6.73 CI 95% 2.79-16.2, P < 0.001), retained deep tendon reflexes (score 18.0/24 vs 11.5/24, R = 0.275, P < 0.001). On pathology, we observed absent/scant regenerative changes (τb = - 0.362, P < 0.001), concomitant involvement of large (100% and 99%, n.s.), small myelinated (97% vs 81%, POR 7.74 CI 95% 1.03-58.4, P = 0.02) and unmyelinated nerve fibers (85% vs 41%, POR 8.52 CI 95% 3.17-22.9, P < 0.001). Cerebellar or vestibular involvement was similarly rare in the two groups. CONCLUSIONS: This study highlights the frequent occurrence of the RFC1 AAGGG repeat expansion in patients diagnosed with CIAP and characterizes the clinical and pathological features of the related neuro(no)pathy.

High Diagnostic Accuracy of RT-QuIC Assay in a Prospective Study of Patients with Suspected sCJD.

The early and accurate in vivo diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) is essential in order to differentiate CJD from treatable rapidly progressive dementias. Diagnostic investigations supportive of clinical CJD diagnosis include magnetic resonance imaging (MRI), electroencephalogram (EEG), 14-3-3 protein detection, and/or real-time quaking-induced conversion (RT-QuIC) assay positivity in the cerebrospinal fluid (CSF) or in other tissues. The total CSF tau protein concentration has also been used in a clinical setting for improving the CJD diagnostic sensitivity and specificity. We analyzed 182 CSF samples and 42 olfactory mucosa (OM) brushings from patients suspected of having sCJD with rapidly progressive dementia (RPD), in order to determine the diagnostic accuracy of 14-3-3, the total tau protein, and the RT-QuIC assay. A probable and definite sCJD diagnosis was assessed in 102 patients. The RT-QuIC assay on the CSF samples showed a 100% specificity and a 96% sensitivity, significantly higher compared with 14-3-3 (84% sensitivity and 46% specificity) and tau (85% sensitivity and 70% specificity); however, the combination of RT-QuIC testing of the CSF and OM samples resulted in 100% sensitivity and specificity, proving a significantly higher accuracy of RT-QuIC compared with the surrogate biomarkers in the diagnostic setting of patients with RPD. Moreover, we showed that CSF blood contamination or high protein levels might interfere with RT-QuIC seeding. In conclusion, we provided further evidence that the inclusion of an RT-QuIC assay of the CSF and OM in the diagnostic criteria for sCJD has radically changed the clinical approach towards the diagnosis.

Sporadic hereditary neuropathies misdiagnosed as chronic inflammatory demyelinating polyradiculoneuropathy: Pitfalls and red flags.

Hereditary neuropathies may be misdiagnosed with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). A correct diagnosis is crucial for avoiding unnecessary therapies and access genetic counseling. We report on nine patients (seven men, mean age 49.2 ± 16.1) diagnosed with and treated as CIDP, in whom mutations or variants of unknown significance (VUS) in genes associated with hereditary neuropathies were reported. All underwent neurological and neurophysiological examination, eight also cerebrospinal fluid (CSF) analysis. In 4/9, nerve ultrasound and/or MR-neurography were performed. All the patients complained of progressive upper or lower limbs sensory-motor symptoms, with heterogeneous disease duration (1-34 years, mean 8.6 ± 10.8). Neurophysiology showed demyelinating signs in seven patients, mixed findings with predominant axonal damage in two patients. Neuroimaging disclosed diffuse abnormalities at proximal and distal segments. Molecular screening showed PMP22 duplication in two patients, mutations in the MPZ, EGR2, and GJB1 genes were reported in each of the remaining patients. The two patients with mixed neurophysiological findings had p.Val30Met mutation in the transthyretin gene. Two patients had VUS in the MARS and HSPB1 genes. Four patients had partial response to immunomodulant therapies, and CSF and neurophysiological features suggesting an inflammatory condition concomitant with the hereditary neuropathy. Hereditary neuropathy may be misdiagnosed with CIDP. The most common pitfalls are CSF (high protein levels and oligoclonal bands), incorrect interpretation of neurophysiology, and transient benefit from therapies. Neuroimaging may be helpful in cases with atypical presentations or when severe axonal damage complicate the neurophysiological interpretation.

Charcot-Marie-Tooth disease: experience from a large Italian tertiary neuromuscular center.

INTRODUCTION: Charcot-Marie-Tooth (CMT) disease is the most common inherited neuromuscular disease. Thanks to the advances of the latest generation sequencing, more than 80 causative genes have been reported to date. METHODS: In this retrospective, observational study, we have analyzed clinical, electrophysiological, and genetic data of CMT patients in care at Neuromuscular Center of Messina University Hospital, Messina, Italy, for at least 22 years (from 1994 to 2016). Our center is the only reference center for genetic neuropathies in Sicily and in the southern part of Calabria. RESULTS: We reviewed the clinical records of 566 patients with the aim to evaluate how many patients received a genetic diagnosis and the distribution of the genetic subtypes. About 352/566 (62.19%) received a genetic diagnosis. The most frequent genetic diagnoses were CMT1A/PMP22 duplication (51.13%), followed by HNPP/PMP22 deletion (15.05%), CMT1B/MPZ mutation (10.22%), CMTX/GJB1 mutation (9.37%), and CMT2F/HSPB1 (4%). Other rare mutations included MFN2 mutation (n. 8 pts), BSCL2 mutation (n.8 pts), PMP22 point mutation (n.7 pts), GDAP1 mutation (n.4 pts), GARSmutation (n. 2 pts), TRPV4 mutation (n. 2 pts), LITAF mutation (n.1 pt), and NEFL mutation (n. 1 pt). CONCLUSIONS: Our study provides further data on frequency of CMT genes, subtypes in a wide Mediterranean area and contributes to help clinicians in addressing the genetic testing workup.

Toward the Authentication of European Sea Bass Origin through a Combination of Biometric Measurements and Multiple Analytical Techniques.

The authenticity of fish products has become an imperative issue for authorities involved in the protection of consumers against fraudulent practices and market stabilization. The present study aimed to provide a method for authentication of European sea bass ( Dicentrarchus labrax) according to the requirements for seafood labels (Regulation 1379/2013/EU). Data on biometric traits, fatty acid profile, elemental composition, and isotopic abundance of wild and reared (intensively, semi-intensively, and extensively) specimens from 18 southern European sources ( n = 160) were collected, clustered in six sets of parameters, and then subjected to multivariate analysis. Correct allocations of subjects according to their production method, origin, and stocking density were demonstrated with good approximation rates (94, 92, and 92%, respectively) using fatty acid profiles. Less satisfying results were obtained using isotopic abundance, biometric traits, and elemental composition. The multivariate analysis also revealed that extensively reared subjects cannot be analytically discriminated from wild subjects.

Diagnosis of Human Prion Disease Using Real-Time Quaking-Induced Conversion Testing of Olfactory Mucosa and Cerebrospinal Fluid Samples.

Importance: Early and accurate in vivo diagnosis of Creutzfeldt-Jakob disease (CJD) is necessary for quickly distinguishing treatable from untreatable rapidly progressive dementias and for future therapeutic trials. This early diagnosis is becoming possible using the real-time quaking-induced conversion (RT-QuIC) seeding assay, which detects minute amounts of the disease-specific pathologic prion protein in cerebrospinal fluid (CSF) or olfactory mucosa (OM) samples. Objective: To develop an algorithm for accurate and early diagnosis of CJD by using the RT-QuIC assay on CSF samples, OM samples, or both. Design, Setting, and Participants: In this case-control study, samples of CSF and OM were collected from 86 patients with a clinical diagnosis of probable (n = 51), possible (n = 24), or suspected (n = 11) CJD and 104 negative control samples (54 CSF and 50 OM). The CSF and OM samples were analyzed using conventional RT-QuIC. The CSF samples underwent further testing using improved RT-QuIC conditions. In addition, the diagnostic performance of a novel, easy-to-use, gentle flocked swab for sampling of OM was evaluated. Data were collected from January 1 to June 30, 2015. Main Outcome and Measures: Correlations between RT-QuIC results and the final diagnosis of recruited patients. Results: Among the 86 patients (37 men [43%] and 49 women [57%]; mean [SD] age, 65.7 [11.5] years) included for analysis, all 61 patients with sporadic CJD had positive RT-QuIC findings using OM or CSF samples or both for an overall RT-QuIC diagnostic sensitivity of 100% (95% CI, 93%-100%). All patients with a final diagnosis of non-prion disease (71 CSF and 67 OM samples) had negative RT-QuIC findings for 100% specificity (95% CI, 94%-100%). Of 8 symptomatic patients with various mutations causing CJD or Gerstmann-Sträussler-Scheinker syndrome, 6 had positive and 2 had negative RT-QuIC findings for a sensitivity of 75% (95% CI, 36%-96%). Conclusions and Relevance: A proposed diagnostic algorithm for sporadic CJD combines CSF and OM RT-QuIC testing to provide virtually 100% diagnostic sensitivity and specificity in the clinical phase of the disease.

Co-occurrence of the C9ORF72 expansion and a novel GRN mutation in a family with alternative expression of frontotemporal dementia and amyotrophic lateral sclerosis.

The C9ORF72 repeat expansion is the major cause of frontotemporal lobar degeneration (FTLD), amyotrophic lateral sclerosis (ALS), and FTLD-ALS. In the reported pedigree, the 47-year old proband, presenting a four-year history of frontotemporal dementia, carried the C9ORF72 expansion plus a novel GRN p.Cys246X mutation. The father and a paternal uncle, harboring the C9ORF72 expansion only, had died by pure ALS with onset at 63 and 76 years, respectively. The case report and a review of the literature emphasize that phenotypical variations of the FTLD-ALS spectrum could be due to digenic inheritance.

A novel PSEN1 mutation in a patient with sporadic early-onset Alzheimer's disease and prominent cerebellar ataxia.

PSEN1 gene mutations represent the first cause of familiar early-onset Alzheimer's disease (EOAD). More than 190 mutations in PSEN1 have been reported to date. The clinical phenotype is mainly characterized by cognitive decline but movement disorders have been rarely described. We report a novel PSEN1 mutation (p.Thr147Pro) responsible for a sporadic early-onset dementia with prominent cerebellar symptoms, resembling a spinocerebellar syndrome. Neuroradiological and cerebrospinal fluid biomarkers examinations were performed on the patient, showing typical findings of EOAD and suggesting the pathogenicity of the novel mutation. Our study widens the number of unusual phenotypes related to PSEN1 mutations.

WEFTA interlaboratory comparison on total lipid determination in fishery products using the Smedes method.

Lipid determination by the Smedes method was tested in an interlaboratory trial performed by nine laboratories from seven countries belonging to the West European Fish Technologists Association Analytical Methods Working Group. Five samples of fish and fishery products with different lipid contents, including two blind duplicates, were distributed among the participants. All laboratories applied a slightly modified Smedes method, which included extraction of lipids by cyclohexane and isopropanol, transfer of lipids to the cyclohexane phase by addition of water, phase separation by centrifugation, and gravimetric lipid determination. The results indicate that the RSD for reproducibility (RSD(R)) was between 4.11 and 6.31% for samples with moderate (7%) and high (14%) lipid content, depending on the sample. Larger SDs among the laboratories were obtained for a cod sample with low lipid content of 0.5%. The method is judged to be suitable as a routine method for lipid determination in fish and fishery products.

Autosomal dominant Alzheimer's disease with early frontal lobe involvement associated with the Met239Ile mutation of Presenilin 2 gene.

Mutations in the Presenilin 2 gene (PSEN2) represent the less frequent genetic cause of familial Alzheimer's disease (FAD). Only eight PSEN2 mutations, reported in approximately 27 families, satisfied strict criteria of pathogenicity. We reported a patient with early-onset FAD and the PSEN2 p.Met239Ile mutation, presenting with severe executive dysfunction and myoclonic tremor, associated with memory loss. Brain SPECT study showed an early hypoperfusion of the frontal cortex. We confirmed the pathogenicity of PSEN2 p.Met239Ile mutation and its heterogeneous phenotypic expression. The modulating effect of the Apolipoprotein E and Prion Protein gene polymorphisms on the phenotypic variability was not confirmed.

Unusual features of central nervous system involvement in CMTX associated with a novel mutation of GJB1 gene.

In this study, we report a novel connexin 32 (CX32) mutation associated with cognitive impairment and a differential degree of peripheral nerve involvement. We present clinical, electrophysiological, and neuroimaging data on a family with X-linked Charcot-Marie-Tooth disease caused by a 41A>G mutation of the gap junction protein beta 1 (GJB1) gene. The proband and her sister presented with a severe neuropathy with subclinical cognitive impairment; the proband's brother showed severe cognitive impairment and a mild neuropathy. This family report confirms that Charcot-Marie-Tooth type X is a clinically heterogeneous group, with great variability of phenotypes, possible severe involvement in females and clinical signs of cognitive impairment. Thus, this novel mutation should be added to the group of CX32 mutations with a central nervous system phenotype.

Déjerine-Sottas syndrome with a silent nucleotide change of myelin protein zero gene.

Charcot-Marie-Tooth disease type 1B (CMT1B) and Déjerine-Sottas syndrome type B (DSSB) are caused by missense or frameshift mutations of myelin protein zero (MPZ) gene. We identified an apparently silent synonymous c.411C>T transition in MPZ exon 3 (p.Gly137Gly) which segregated with DSS in a two-generation pedigree. Retro-transcriptional analysis of MPZ in the proband's archive sural nerve biopsy identified an r.410_448del mutant transcript which resulted from an activated cryptic splice site in exon 3 and led to an in-frame partial deletion of exon 3 (p.Gly137_Lys149del). Quantitative real-time polymerase chain reaction (QRT-PCR) compared with two unrelated CMT1B nerves carrying a frameshift c.306delA mutation (p.Asp104ThrfsX13) indicated that the r.410_448del was stable differing from the p.Asp104ThrfsX13-associated transcript which was subjected to nonsense-mediated decay. The report highlighted the possible pathogenic role of synonymous MPZ mutations and difficulties in interpreting results from routine mutational screenings.

Pitfalls in diagnosing mitochondrial neurogastrointestinal encephalomyopathy.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder caused by mutations in the gene encoding thymidine phosphorylase and is characterized by external ophthalmoparesis, gastrointestinal dysmotility, leukoencephalopathy, and neuropathy. The availability of new therapeutic options (peritoneal dialysis, allogeneic stem cell transplantation, enzyme replacement) makes it necessary to diagnose the disease early, which is not always achieved due to the difficulty in recognizing this disorder, especially in case of atypical presentation. We describe three MNGIE patients with atypical onset of the disease. In the first patient the main symptoms were long-standing chronic fever, recurrent acute migrant arthritis, and gastrointestinal disorders mimicking autoimmune or inflammatory intestinal diseases; the second patient complained only of exercise intolerance and muscle cramps, and the third patient had a CIDP-like polyneuropathy. This study stresses the insidious heterogeneous clinical onset of some cases of MNGIE, expands the spectrum of the phenotype, and suggests considering MNGIE in the differential diagnosis of enteropathic arthritis, isolated exercise intolerance, and inflammatory polyneuropathies not responsive to the usual treatment. A better understanding of the clinical heterogeneity of MNGIE is necessary in order to diagnose atypical cases and promote early diagnosis, which is now absolutely necessary in view of the new available therapies.

Metabolomics as a powerful tool for molecular quality assessment of the fish Sparus aurata.

The molecular profiles of perchloric acid solutions extracted from the flesh of Sparus aurata fish specimens, produced according to different aquaculture systems, have been investigated. The (1)H-NMR spectra of aqueous extracts are indicative of differences in the metabolite content of fish reared under different conditions that are already distinguishable at their capture, and substantially maintain the same differences in their molecular profiles after sixteen days of storage under ice. The fish metabolic profiles are studied by top-down chemometric analysis. The results of this exploratory investigation show that the fish metabolome accurately reflects the rearing conditions. The level of many metabolites co-vary with the rearing conditions and a few metabolites are quantified including glycogen (stress indicator), histidine, alanine and glycine which all display significant changes dependent on the aquaculture system and on the storage times.